GIFT   OF 
Mrs*  Burton  F.   Dinsmore 


Steam  Economy  in  the 
Sugar  Factory 


BY 
KARL    ABRAHAM 

Civil  Engineer 


TRANSLATED  FROM  THE  GERMAN  EDITION 

BY 

E.  J.  BAYLE 

General  Engineer,  American  Beet  Sugar  Company 


FIRST  EDITION 
FIRST  THOUSAND 


NEW   YORK 

JOHN    WILEY    &    SONS 

LONDON:   CHAPMAN   &   HALL,   LIMITED 

1912 


COPYRIGHT,  1912, 

BY 
E.  J.  BAYLE 


Stanbopc  jpreas 

F.    H.GILSON   COMPANY 
BOSTON,  U.S.A. 


TRANSLATOR'S  PREFACE. 

IN  preparing  this  book  the  translator  has  had  in  mind1 
primarily  the  dissemination  of  information  relative  to 
the  methods  resorted  to  in  the  older  sugar  producing 
countries.  His  own  needs,  as  well  as  those  of  his  staff, 
concerning  the  proper  distribution  and  management 
of  steam  in  sugar  factories,  for  the  purpose  of  effecting 
economies  in  the  same,  have  also  been  an  incentive 
towards  its  publication. 

After  devoting  many  years  to  the  designing  of  cane 
sugar  apparatus  and  factories,  he  engaged  in  the  beet 
sugar  industry,  and,  finding  no  books  in  the  English 
language  which  would  answer  his  purpose,  he  undertook 
the  translation  of  Mr.  Abraham's  work,  which,  to  his 
mind,  is,  up  to  the  present,  the  best  work  on  the  subject. 

Since  making  the  translation  of  this  book  several 
years  ago,  the  writer  has  had  the  advantage  of  visiting 
typical  beet  sugar  factories  throughout  Italy,  Austria- 
Hungary,  Germany,  Belgium,  Holland,  France  and 
Spain,  giving  special  attention  to  those  which  elaborate 
white  sugar,  and  has  become  more  fully  convinced  of  its 
value  and  of  its  profitable  application  to  the  methods 
resorted  to  in  the  United  States. 

He  hopes,  therefore,  that  it  will  meet  a  real  want  in  all 
sugar  factories  and  perhaps  also  be  of  some  little  assist- 
ance to  those  technical  schools  which  have  a  course  in 
Sugar  Engineering. 


IV  PREFACE 

English  standards  being  commonly  used  in  this  country 
for  the  determination  and  calculation  of  the  calorific 
value  of  fuels  and  the  capacities  and  heating  surfaces 
of  apparatus,  the  formulas  and  tables  in  the  German 
book  have,  for  convenience,  been  converted  into  these 
standards. 

In  conclusion,  the  translator  expresses  the  hope  that 
the  publication  of  this  work,  written  during  the  spare 
moments  of  a  very  active  engineering  life,  may  be  of 
assistance  towards  making  clear  some  of  the  considera- 
tions, both  technical  and  practical,  which  are  necessary 
in  the  design  and  construction,  as  also  in  the  operation, 
of  sugar  apparatus,  and,  in  this  way,  contribute  towards 
promoting  the  application  of  scientific  principles  to  the 
many  problems  presented  to  the  sugar  men  of  to-day. 

Although  the  work  has  been  carefully  checked,  errors 
may  have  crept  in  in  printing,  and  he  will  be  obliged  for 
any  notification  of  these. 

E.  J.  BAYLE. 
DENVER,  COLO.,  August,  1912. 


STEAM    ECONOMY  IN    THE 
SUGAR  FACTORY 


INTRODUCTION. 

WHEN  considering  the  subject  of  this  book  and  its 
scope,  it  occurred  to  me  that  it  would  be  better  to  select 
one  method  of  elaboration  and  to  consider  fully  this  one 
method,  accompanying  the  discussion  of  the  same  with 
as  many  examples  as  possible.  I  selected  the  elaboration 
of  white  crystal  sugar  with  two  products,  as  it  is  carried 
on  throughout  Russia  and  will  probably  also  be  carried 
on  elsewhere  in  the  future.  In  order  to  be  understood,  I 
will  describe  the  process  briefly  in  a  general  way. 

The  raw  juice,  having  been  heated  to  176-185°  F.,  is 
treated  with  from  2%  to  4%  lime  and  generally  satu- 
rated with  three  intermediate  nitrations  of  graded  stages, 
and  usually  the  last  |%  of  lime  is  added  before  the 
second  saturation. 

The  temperatures  are  dealt  with  very  differently  in 
the  first  and  second  saturations  and  this  appears  to  be  of 
little  importance  with  sound  beets  and  normal  work. 
The  third  saturation  is  more  often  carried  on  with  sul- 
phurous acid.  After  the  scum  presses  generally  come 
refilters.  Previous  to  its  entrance  into  the  evaporating 
station,  the  juice,  almost  without  exception,  is  filtered 
twice  and  generally  boiled  thereafter  before  the  final 
filtration.  Where  the  thin  juice  has  not  been  sulphured, 


2  STEAM    ECONOMY 

this  is  more  frequently  done  with  the  intermediate  (half- 
concentrated)  juice.  There  are,  however,  some  factories 
which  secure  the  brightest^white  crystals  without  sul- 
phuration.* 

Nowadays,  the  first  product  is,  with  good  reason, 
generally  spun  off  warm,  i.e.,  immediately  after  its 
discharge  from  the  pans.  As  soon  as  the  centrifugal  is 
at  full  speed,  it  is  washed  with  a  second  product,  which 
is  somewhat  diluted  (40  to  60°  Brix)  and  then  with 
steam.  The  finished  white  sugar  which  comes  warm  from 
the  centrifugals  is  conveyed  into  a  cooling  and  drying 
drum,  which  commonly  has  a  sieve  at  its  end,  and  then 
goes  into  the  bag. 

The  discharge  is  usually  divided  automatically  into 
two  and  at  times  three  grades. 

The  higher  grade  discharge  is  collected  usually  in  such 
quantity  (and  brought  back  into  the  process),  that  it  is 
possible,  without  boiling  the  first  product  very  stiffly,  to 
obtain  a  green  syrup,  of  not  over  74%  purity.  Before 
being  dropped  the  first  product  is  thinned  down  in  vacuo 
with  about  10%  of  previously  heated  second  product  and 
then  dropped  into  the  mixer. 

The  second  product  is  boiled  to  crystals,  agitated  for 
from  three  to  five  days  and  spun  off  at  about  ii3°F. 
without  steam.  Ordinarily  there  is  given  to  the  very 

*  For  a  long  time  it  was  not  clear  to  me  at  which  point  it  would  be 
best  to  introduce  SO2.  I  believe  I  have  reached  the  final  conclusion, 
that  the  saturation  of  the  intermediate  juice  before  the  last  body  of  the 
evaporators  (at  from  about  40  to  50°  Brix.)  is  best,  provided  that  it  be 
throughly  filtered  before  and  after  sulphuration.  Assuredly  the  filtra- 
tion preceding  appears  to  be  of  great  importance. 


INTRODUCTION  3 

stiffly  boiled  second  product  in  vacuo  before  the  dropping, 
and  if  need  be  also  in  the  mixer,  an  addition  of  hot  third 
product,  according  as  the  massecuite  thickens. 

This  is  done  in  order  to  constantly  keep  farther  apart 
the  somewhat  softer  crystals,  so  that  they  may  float  freely 
and  thus  be  protected  against  grinding,  and  to  prevent 
the  formation  of  small  grains.  The  raw  sugar  from  the 
second  product  is  dissolved  and  brought  back  into  the 
process.  When  it  is  intended  to  produce  the  best  quality 
of  crystal  sugar,  from  not  too  favorable  beet  material,  it 
would  be  necessary  to  proceed  more  cautiously  with  the 
reintroduction  of  the  green  syrup. 

One  must  be  contented  with  a  higher  purity  green 
syrup  from  the  first  product  and  thus  secure  a  corre- 
spondingly higher  second  product,  which  results  in  a 
greater  amount  of  the  hot  third  product  in  the  vacuum 
pan  and  the  mixer,  in  order  to  sufficiently  lower  the 
purity  quotient  and  to  give  the  crystals  the  proper 
protection,  which  is  more  certain  to  occur  with  a  crystal 
content  of  not  over  40%  to  45%. 

The  green  syrup  from  the  second  product,  as  it  comes 
from  the  centrifugals,  is  sometimes  filtered  without 
dilution,  after  having  been  properly  heated,  which  seems 
to  be  a  very  rational  practice.  A  previous  chemical 
treatment,  as  it  is  sometimes  met  with,  appears  to  have 
no  greater  advantage  than  such  a  simple  filtration. 

As  regards  the  reintroduction  of  the  green  and  of  the 
dissolved  raw  sugar,  a  great  difference  of  opinion  prevails. 
Its  introduction  into  the  second  saturation  is  the  more 
common  practice;  recently  also  the  special  treatment 


4  STEAM    ECONOMY 

with  lime  and  carbonic  acid,  its  addition  to  the  inter- 
mediate juice  after  being  filtered,  and  the  sulphuring  of 
the  whole. 

To  me  it  seems  most  important  that  the  green  syrup 
and  solutions  of  raw  sugar,  which  always  contain  some 
superheated  products,  should  be  somewhere  thoroughly 
boiled  with  lime.  The  simpler  and  the  cheaper  this  can 
be  accomplished,  the  better.* 

Whether  the  methods  of  work  be  the  one  or  the  other, 
the  conclusions  to  be  drawn  always  remain  the  same. 
The  following  tables  also,  except  13,  are  applicable  to 
every  method  of  operation. 

With  the  given  tables  any  one  can  figure  out  for  him- 
self the  consumption  of  steam  for  each  individual  case 
according  to  the  methods  outlined,  or  he  can  read  it 
directly  from  the  tables. 

In  the  same  way  every  departure  from  the  common 
method  of  operation  as  regards  steam  consumption  can 
be  easily  determined. 

In  the  first  place,  I  will  explain  the  steam  consumption 
of  the  individual  stations,  elucidate  the  conditions  which 
influence  this  consumption,  and  then  dwell  upon  the 
systems  for  utilization  of  steam,  which,  independently 
of  the  individual  use,  have  for  their  aim  the  reduction  of 
the  total  steam  consumption. 

While  I  give  a  very  short  guide  for  the  figuring  of 
heating  surfaces,  I  have  intentionally  avoided  giving 
definite  information  relative  to  coefficients  of  trans- 
mission for  each  separate  station,  since  they  are  change- 

*  For  further  detail  refer  to  page  26. 


INTRODUCTION  5 

able  and  very  dependent  upon  the  details  of  construction 
and  the  methods  of  operation. 

In  any  sugar  factory  it  is  not  difficult  to  determine  the 
coefficients  for  this  or  that  station  under  the  prevailing 
conditions.  The  designer  of  a  new  apparatus  must  have 
such  experience  as  to  enable  him  to  see  his  way  clear  in 
any  single  case. 

In  general  it  should  be  recommended,  not  to  rely  too 
much  upon  the  information  to  be  found  in  literature, 
as  it  has  too  often  the  imprint  of  favoritism.  When 
the  information  comes  from  inventors  this  is  a  matter 
of  course.  Or  else  the  very  best  information  is  given  in 
order  not  to  cast  any  reflection  on  the  user  by  insinu- 
ating that  he  did  not  know  how  to  keep  the  apparatus 
in  the  proper  operating  condition. 


THE  STEAM   CONSUMPTION   OF  THE  INDI- 
VIDUAL  STATIONS. 

i.   DIFFUSION. 

IN  the  process  of  diffusion,  cossettes  at  a  temperature 
of  from  32  to  60°  F.  are  introduced,  and  raw  juice  at  from 
68  to  104°  F.  is  drawn  off;  fresh  water  of  varying  tem- 
perature is  introduced  and  the  pulp  and  the  battery 
waste  water  are  discharged  at  a  temperature  only  a  few 
degrees  higher  than  that  of  the  fresh  water. 

There  are  two  reasons  for  the  consumption  of  heat  at 
this  station :  First,  the  loss  of  heat  through  the  radiation 
from  the  cells  and  accessories,  calorizators,  pulp  strainers 
and  measuring  tanks.  Second,  the  fact  that  in  the 
products  (juice  and  watery  pulp)  of  diffusion,  there  is 
always  more  heat  than  in  the  introduced  (cossettes  and 
fresh  water)  materials. 
Let  us  assume : 

100  pounds  of  cossettes  introduced; 
tr  =  temperature  of  cossettes  introduced; 
c  =  heat  capacity  of  cossettes  for  diffusion  without 

rinsing  water; 
W  =  per  cent  water  used; 
tw  =  temperature  of  water  used; 
S  =  per  cent  of  soaked  cossettes  and  diffusion  water 
(as  is  contained  in  the  diffusion  cell  before  its 
discharge) ; 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS     7 

n°  =  difference    between   temperature   of   cell  at 

discharge  and  temperature  of  water  used; 
100  +D  =  per  cent  draw  of  diffusion  juice; 
td  =  temperature  of  diffusion  juice; 
c1  =  heat  capacity  of  juice; 
V  =  heat  loss  through  radiation  ; 
/  =  heat  capacity  of  the  water-soaked  pulp  ; 

then  the  heat  consumption  for  diffusion  can  be  expressed 

as  x. 
Whence  : 

x  =  V  +  (ioo+D)c1td+S(tw+n)-(iooctr  +  Wtw).     (i) 


which  means  that  the  heat  consumption  equals  the  loss 
through  radiation,  plus  the  difference  in  the  quantities 
of  heat  which  are  present  in  the  products  and  the 
materials  of  diffusion  (above  32°  F.). 

Since  the  weight  of  the  materials  of  diffusion  (water 
and  beets)  must  naturally  be  equal  to  the  weight  of  the 
product  (juice  and  pulp),  the  following  equation  can 
then  be  written  : 


hence  W  =  D  +  S   ......     (2) 

If  we  set  down  in  equation  (i)  instead  of  W  its  value 
out  of  (2)  we  have 

x  =  V  +  Sn  +  100  (cltd  -ctr)  -  D  (tw  -  cltd).     (3) 

This  equation  permits  the  exact  determination  of  the 
heat  consumption  of  diffusion  from  the  known  values 
introduced  therein. 


8  STEAM    ECONOMY 

For  practical  purposes  we  can  say  that 
5  =  200   and   c  —  cl  =  0.9*- 
Then  x=V +2oon+go(td-tr) -D(tw-o.gQ,  .     .     (4) 

from  which  it  is  apparent  that  the  consumption  of  heat 
in  the  diffusion  is  lower  the  less  the  temperature  dif- 
ference between  the  juice  and  the  cossettes,  the  warmer 
the  introduced  water  and  the  colder  the  drawn-off  juice. 
This  last  equation  shows  likewise  that  as  long  as  the 
temperature  of  the  water  is  higher  than  0.9  times  the 
temperature  of  the  juice,  the  heat  consumption  diminishes 
with  the  increased  draw  of  the  battery. 

The  loss  of  heat,  V,  occasioned  by  radiation  can  be 
calculated  approximately  for  every  given  diffusion  and 
all  conditions  of  work,  with  due  regard  to  the  radiating 
surfaces  and  their  temperatures,  with  the  assistance  of 
existing  tables  (Hausbrandt) ,  or  it  can  be  ascertained 
by  means  of  direct  experiments.  Such  determinations 

*  Assuming  that  the  heat  capacity  of  the  juice  equals  the  sum  of  the 
heat  contained  in  the  water  and  the  heat  contained  in  the  sugar,  then 

the  specific  heat  can  be  calculated  from  the  formula 

100 

in  which  B  =  degrees  Brix  and  0.301  equals  the  heat  capacity  of  the 
sugar  according  to  Kopp. 

From  this  equation  the  following  values  are  obtained: 

Degree  Brix  of  solution     10      20     30      40     50     60      70     80     90 
Heat  capacity  0.93  0.86  0.79  0.72  0.65  0.58  0.51  0.44  0.37 

In  fact  it  is  even  somewhat  lower  because  of  the  contraction  during 
the  process  of  dissolving  and  because  of  the  lower  heat  capacity  of  the 
nonsugar. 

For  this  reason  it  is  not  permissible,  as  usual,  to  make  the  heat  capa- 
city of  the  juice  equal  to  unity. 


STEAM    CONSUMPTION    OF  INDIVIDUAL    STATIONS     9 

were  made  by  Czerny  and  Hauner  and  they  found  V  = 
888,  as  against  Shaper  only  342.  Naturally  these 
figures  must  be  subject  to  great  variations,  according  to 
the  size  of  the  diffusion  battery  and  the  existing  insula- 
tion. The  high  figure  of  Czerny  and  Hauner  is  made 
plain  by  the  fact  that  the  determination  was  carried  on 
with  a  very  small  battery  (29.6  cubic  feet). 

The  difference  in  temperature  n  between  the  water  and 
the  pulp  discharged  depends  on  the  length  of  the  battery 
and  the  distribution  of  the  temperature. 

The  farther  the  heating  is  carried  from  the  water  end, 
the  smaller  n  will  be  and  vice  versa.  This  can  vary  in 
limits  between  2°  and  9°  and  must  be  determined  by 
means  of  simultaneous  measurement  of  the  temperature 
of  the  water  and  the  temperature  at  the  center  of  the 
diffusion  cell  before  discharging. 

In  order  to  find  the  steam  consumption,  X1,  from  the 
heat  consumption  per  100  pounds  of  beets,  it  suffices 
to  divide  the  result  of  equation  (4)  by  the  number  of 
heat  units,  which  are  carried  over  per  pound  of  steam 
for  the  existing  conditions  in  the  diffusion,  namely, 
about  970  B.t.u.'s,  whence 

jp    _      V     _j_200tt  +  9o(k  -  tr)   ~D(tw  -O.Qp^      xv 

970       970  970 

The  first  member  of  this  equation  gives  the  steam  loss 
occasioned  by  the  radiation,  the  second  the  loss  through 
the  useless  heating  of  the  contents  of  the  last  diffusion 
cell,  and  the  last  the  profitable  steam  consumption, 
which  is  of  benefit  to  the  stations  next  following.  If  we 


10 


STEAM    ECONOMY 


TABLE   i. 
Steam  and  Heat  Consumption  for  Diffusion  of  TOO  Pounds  of  Beets. 


Draw. 

100% 

110% 

Temperature 
difference 
between  the 
juice  and  the 
cossettes. 

Difference  between  the  temperature  of  water  and  0.9  the 
temperature  of  juice  (tw  —  0.9  Id). 

0 

10 

20 

30 

40 

o 

10 

20 

30 

40 

td-tr 

Steam  consumption  per  100  pounds  beets;  the  total 
heat  in  B.t.u's  below. 

10°..           ..] 

2-93 
2844 
3.86 
3744 
4.78 
4644 
5-7i 
5544 
6.63 
6444 
7-57 
7344 
8.50 
8244 

2-93 
2844 
3-86 
3744 
4.78 
4644 
5-71 
5544 
6.63 
6444 
7-57 
7344 
8.50 
8244 

2-93 
2844 
3.86 
3744 
4.78 
4644 
5-71 
5544 
6.63 
6444 
7-57 
7344 
8.50 
8244 

2-93 
2844 
3.86 
3744 
4.78 
4644 
5-7i 
5544 
6.63 
6444 
7-57 
7344 
8.50 
8244 

2-93 
2844 
3.86 
3744 
4.78 
4644 
5-7i 
5544 
6.63 
6444 
7-57 
7344 
8.50 
8244 

2*93 

2844 

3-86 
3744 
4.78 
4644 
5-7i 
5544 
6.63 
6444 
7-57 
7344 
8.50 
8244 

2.83 

2744 
3-76 
3644 
4.68 

4544 
5-6o 

5444 
6-54 
6344 
7.46 
7244 
8.40 

8i44 

2.72 
2644 
3.66 

3544 
4-57 
4444 
5-50 
5344 
6-43 
6244 

7.36 
7144 
8.30 

8044 

2.62 
2544 
3-55 
3444 
4-47 
4344 
5-40 
5244 
6-33 
6144 

7-25 
7044 
8.19 
7944 

2.52 
2444 
3-45 
3344 
4-37 
4244 
5-30 
5144 

6.22 

6044 

7-15 
6944 
8.08 
7844 

I 

( 

30° 

6                    1 

40°.  .        .  .  -i 

I 
50° 

5     I 

*  i 
70°..        .. 

/ 

Draw. 

120% 

130% 

Temperature 
difference 
between  the 
juice  and  the 
cossettes. 

Difference  between  the  temperature  of  water  and  0.9 
the  temperature  of  juice  (tw  —  0.9  /<$). 

o 

10 

20 

30 

40 

0 

10 

20 

30 

40 

td-  tr 

Steam  consumption  per  loo  pounds  beets;  the  total 
heat  in  B.t.u's  below. 

10°..          ..{ 

2.Q3 

2844 
3-86 
3744 
4.78 
4644 
5-7i 
5544 
6.63 
6444 
7-57 
7344 
8.50 
8244 

2.72 
2644 

3-66 
3544 
4-57 
4  4  14 

2.52 
2444 
3-45 
3344 
4-37 
4244 
5-30 
5144 

6.22 

6044 
7-15 
6944 
8.08 
7844 

2.32 
2244 
3-24 
3!44 
4-17 
4044 

5-09 
4944 

6.02 

5844 
6-95 
6744 
7.78 
7644 

2.  II 
2044 
3-03 
2944 
3-96 
3844 
4-89 

4744 
5-8i 
5644 
6.74 
6544 
7.67 
7444 

2-93 

2844 
3-86 
3744 
4.78 
4644 
5-7i 
5544 
6.63 

6444 
7-57 
7344 
8.50 
8244 

2.62 
2544 

3-55 
3444 
4-47 
4344 
5-40 
5244 
6-33 
6i44 
7-25 
7044 
8.19 
7944 

2.32 
2244 
3-24 
3141 
4-17 
4044 

5-°9 
4944 
6.  02 

5844 
6-95 
6744 

7-78 
7644 

2.OO 

1944 
2.92 
2844 

3-86 

3744 
4-78 
4644 
5-7i 
5544 
6.64 
6444 
7-57 
7344 

1.69 
1644 
2.62 
2544 

3-55 
3444 
4-47 
4344 
5-40 
5244 
6-33 
6i44 
7-25 
7044 

I 

20° 

1 

30°..        .. 

6                        } 
40°..        .. 

5-50 
5344 
6-43 
6244 

7.36 
7141 
8.30 
8044 

I 
50° 

5               "] 
60°.. 

( 

£  I 

STEAM    CONSUMPTION   OF    INDIVIDUAL    STATIONS.   II 

assume  the  total  of  the  two  first  members  equal  to  2% 
(that  is,  1944  B.t.u.'s  per  100  pounds),  which  in  most 
cases  probably  proves  correct,  then  the  heat  consumption 
and  the  steam  consumption  can  be  read  direct  for  dif- 
ferent conditions  from  the  preceding  table. 

With  partly  frozen  beets,  as  happens  occasionally  in 
winter,  the  heat  consumption  per  pound  of  ice  is  about 
144  B.t.u.'s  and  the  steam  consumption  about  ij-f-g-  = 
9.148%  higher. 

There  is  contained  in  the  cossettes  10      20       30      40      50  %  ice. 
The  steam  consumption  is  1.48    2.96    4.44    5.93  7.41  %  higher. 

The  heat  consumption  is  1440  2880  4320  5760  7200  B.t.u.'s 

Up  to  the  present  it  has  been  assumed  that  the  dif- 
fusion was  carried  on  with  only  one  kind  of  water.  If, 
for  some  reason  or  other,  the  diffusion  is  carried  on  with 
two  kinds  of  water,  i.e.,  clear  or  warmer  water  for  dif- 
fusing and  cold  or  waste  water  for  drawing  off,  the  heat 
consumption  is  exactly  the  same  as  if  only  one  kind  of 
water  had  been  used,  as  the  last  water  plays  no  part  in 
the  diffusion  proper.  It  is  only  necessary  that  n  be 
determined  by  testing  with  the  first  kind  of  water.  If 
the  last  cell  be  emptied  with  air,  the  result  remains  ex- 
actly the  same,  as  long  as  the  readings  for  determining 
the  value  of  n  are  taken  previous  to  the  introduction 
of  the  air. 


12  STEAM    ECONOMY 


II.  HEATERS. 

Let  again,  as  before,  the  draw  of  the  juice  be  equal  to 
100  +  D  per  cent,  the  temperature  of  the  juice  before 
the  heating  td,  after  heating  /,  its  heat  capacity  c1,  then 
the  heat  capacity  per  100  pounds  of  beets  equals 

cl  (100  +  D)(t-  td) 

and  the  heat  consumption,  if  970  B.t.u.'s  are  transferred 
per  pound  equals 

cl  (IOQ  +£>)(/-  td) 
97° 

According  to  this  the  following  Table  2  is  calculated; 
in  which,  for  the  sake  of  simplicity,  c1  is  set  as  equal 
to  0.9. 

If  for  still  greater  accuracy,  instead  of  c1  its  value 

,      B  X  0.301  +  (100  -  B)       , 
c1  =  -  *-  — ,  wherein  B  is  the  degree 

Brix,  may  be  substituted  in  the  formula. 

The  table  shows  that  with  proportionate  temperature 
differences  the  steam  and  heat  consumption  are  directly 
proportional  to  the  draw  of  the  juice. 

The  steam  consumption  for  intermediate  tempera- 
tures is  easy  to  determine  by  the  use  of  Table  2. 

EXAMPLE  i.  —  How  much  is  the  steam  consumption  for  the 
heating  of  the  juice  from  86°  to  183.2°  with  120%  draw?  The 
difference  183.2°  -  86°  =  97.2°. 


STEAM    CONSUMPTION    OF   INDIVIDUAL    STATIONS    13 


For  90°  difference,  %  steam  used  is 10.02 

For  70°  difference,  %  steam  used  is 7.79 

Then  for  7°  difference,  %  steam  used  is  ...       0.779 
For  20°  difference,  %  steam  used  is 2^,2 

Then  for  0.2°  difference,  %  steam  used  is.       0.022 

Then  for  97.2°  the  %  steam  —  Total  10.822 

TABLE  2. 
Steam  and  Heat  Consumption  of  the  Heaters  per  100  Pounds  of  Beets. 


Degrees  difference  between  juice  leaving  heater  and  juice  entering 
heater  (t  —  td). 


Juice  draw. 

10 

20 

30 

40 

50 

60 

70 

80 

90 

Steam  consumption  per  100  pounds  of  beets.    The  quantity  of  heat 

in  B.t.u's  under  same. 

( 

O.Q3 

1.85 

2.78 

3-71 

4.64 

5-57 

6.49 

7.42 

8-35 

100  /O-  •  •   ^ 

900 

I800 

2700 

3600 

4500 

5400 

6300 

7200 

8100 

1  .02 

2.04 

3-06 

4.08 

5.10 

6.12 

7-  Z4 

8.16 

9.18 

IIO/o.  .  .   j 

990 

1980 

2970 

3960 

4950 

5940 

6930 

7920 

8910 

c/          ( 

1  .11 

2.  22 

3-34 

4.46 

5-57 

6.67 

7-79 

8.90 

IO.O2 

I2O/0.  .  .   j 

1080 

2l6o 

3240 

4320 

5400 

6480 

7560 

8640 

9720 

130%...  1 

1  .20 
1170 

2.41 
2340 

35io 

4.82 
4680 

6.03 
5850 

7-25 
7020 

8-44 
8190 

9-65 
9360 

10.85 
10,530 

140%...  1 

1.30 
1260 

2.60 
252O 

3-90 
3780 

5-20 

5040 

6.49 
6300 

7-78 
7560 

8.98 
8820 

10.38 
10,080 

11.78 

Degrees  difference  between  juice  leaving  heater  and  juice  entering 

heater  (t  —  tj,). 

Juice  draw. 

100 

1  10 

120 

130 

140 

150 

160 

Steam  consumption  per  100  pounds  of  beets.    The  quantity  of  heat 

in  B.t.u  s  under  same. 

ioo%...  j 

9.28 
9000 

10.20 
9900 

II.  12 

10,800 

12.05 
11,700 

12.98 
12,600 

13,500 

14.83 
14,400 

1  10<*            1 

IO.2O 

II  .22 

12.24 

13.26 

14.28 

I5-30 

16.32 

110%..  .  j 

9900 

10,890 

1  1,  880 

12,870 

13,860 

14,850 

15,840 

07           j 

II  .  12 

12.23 

13-34 

14.46 

15-58 

16.79 

17.80 

I20/0...    j 

IO,800 

I  I,  880 

12,960 

14,040 

15,120 

l6,200 

17,280 

°7        \ 

12.05 

13-25 

14.46 

15.66 

16.87 

18.08 

19.28 

I3°/o-  •  •  "j 

II,7OO 

12,870 

I4,O4O 

15,200 

16,380 

17,550 

18,720 

140%...  | 

12.98 
I2,6OO 

14.28 
13,860 

15-58 
15,120 

16.88 
16,380 

18.18 
17,640 

19.48 
18,900 

20.87 
20,140 

14  STEAM    ECONOMY 

III.  THE  SATURATION  OF  THE  THIN  JUICE. 

Whatever  may  be  the  subdivisions  as  regards  the 
saturation  of  the  thin  juice  (two  or  three  separate 
stations)  and  whatever  the  process  may  be,  it  depends,  on 
the  whole,  on  the  following  steps:  (i)  The  addition  (at 
one  or  two  times)  of  a  determined  quantity  of  milk  of 
lime  or  of  unslacked  lime,  and  then  of  a  corresponding 
quantity  of  sweet  water  from  the  presses.  (2)  The 
saturation  in  two  or  three  consecutive  stages  with  inter- 
mediate nitration.  (3)  The  heating  at  different  inter- 
vals, and  ultimately  to  the  boiling  point. 

In  order  to  make  the  calculations  relating  to  the  steam 
and  heat  consumption,  we  will  have  to  evolve  first  some 
auxiliary  values,  which  are  compiled  in  the  following 
Table  3. 

The  saturation  gas  contains  greatly  varying  quantities 
of  carbonic  acid:  14%  to  17%  by  volume,  if  the  gas  be 
taken  out  from  the  rear  of  boilers,  fired  with  wood ;  20% 
to  32%,  if  from  lime  kilns.  According  to  its  weight, 
the  contents  of  carbonic  acid  are  greater,  as  indicated 
by  line  2,  wherein  the  weight  of  a  cubic  foot  of  CO2  is 
equal  to  0.1226  pounds  and  of  the  other  gases  equal  to 
0.0814  pounds.  Of  that  amount  of  carbonic  acid,  only 
a  portion  is  absorbed  by  the  juice,  from  45%  to  65%, 
that  much  the  less,  the  warmer  the  juice  and  the  lower 
the  original  content  of  carbonic  acid. 

As  regards  this,  line  3  gives  the  approximate  percent- 
age by  weight  of  the  consumed  C02  and  line  4  that 
portion  of  the  carbonic  acid  contained  in  the  gas  which  is 


STEAM    CONSUMPTION    OF   INDIVIDUAL    STATIONS    1 5 


S    i 

B     S 

S  <3 


O    O^  1O  ''d"  CO  O    CN    t^-vO  ^O    ^   O^  1O 

M      (N 


10  ^t  O    O\  co  O    co  t~-\O    O  <N  OO    O 
04    co  CN   10  co  t^*oO    M    10  O 

H     M     CO 


\O   <N   r^ 
O  OO   »o  co  10  O 


M     QOO     t^-O     t^-COM( 
CN     W     ^  OO     t^   5J     IJ' 

M     CN     (N 


l!Ig 


a  a  a 


<U    O)    (U    0) 
^   -M   -^   -(J 

o3   oS   oj   o3 


s 


03    C    fe    P.          <*>  +J-U-U-P^-(J 

Q   O         Q^  ^HH^c3c3o3ctfc3ctf 
tt  t  *^    K^  03    C    ^  ^j    o^    O    QJ    C^    Q^    (U 

o  se^  c*«  a  a  a  a  a  a 

•S  °^^^  o  o ^ ,3 3 3 3  x 
§*&  g.2^  JJ-g  o  o  o  o  o  o 


.T5  o 

^  "1~< 

u-^rd  b  b  b  b  b 


H  rM     ^J     O     QH  rH     <I)     QJ     QJ     QJ     QJ     QJ     QJ 
T^ttfW     W  -^    r>^tHUtHUU.U. 


H    N    CO  Tt-  IOVO    t^OO     O  O     M     <N     CO 


given 
ic  foot 


Fi 
* 


16  STEAM    ECONOMY 

thereby  utilized.  Naturally  the  values  of  lines  3  and  4 
cannot  always  be  considered  as  fixed,  -as  these  depend 
not  only  on  the  temperature  and  carbonic  acid  content, 
but  also  on  the  column  of  the  juice,  the  distribution  of 
gas,  the  alkalinity  and  the  quality  of  the  juice. 

Since,  for  the  neutralization  of  a  pound  of  CaO,  f -f  = 
0.786  pound  of  C02  are  necessary,  then  the  weight  of 
the  saturation  gas  which  is  requisite  for  the  precipita- 
tion of  one  pound  of  lime  is  found  by  dividing  ||  X  100 
by  the  percentage  (by  weight)  of  CC>2  utilizable.  The 
result  is  given  on  line  5. 

After  subtracting  the  actually  consumed  0.786  pound 
C02  from  the  numbers  on  line  5,  the  quantity  of  gas  is 
found  which,  considered  as  dry,  escapes  out  of  the 
saturation.  This  is  given  on  line  7. 

In  order  to  pass  from  the  weight  of  the  escaping  gas 
to  its  volume  at  32  degrees,  the  values  must  be  divided 
by  the  weight  of  one  cubic  foot,  which  is  assumed  as 
being  0.0848  pound.  These  are  the  values  of  line  8. 

These  quantities  of  escaping  gas  are  also  heated  up  to 
the  temperature  of  the  juice  and  at  the  same  time 
saturated  with  steam.  These  two  circumstances  occa- 
sion an  expansion  of  the  gas  according  to  the  equation 
yi  =  V  /*  +  459-2\  /  29.92  \ .  Here  y  is  the  volume  Qf 

\      491.2      /  \29.Q2  —  S] 

the  dry  gas  at  o  degree  (also  corresponding  to  the  values 
of  line  8),  /,  the  temperature  after  leaving  the  juice,  and  s, 
the  tension  of  the  steam  at  P.  According  to  this  formula 
lines  9  and  13  are  computed. 

The  steam  consumption  during  the  process  of  satura- 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS     17 

tion  is  made  up  of  several  items  which  are  hereafter  set 
forth  in  their  regular  order. 

(-4)  The  heating  of  the  juice  from  the  temperature  at 
which  it  leaves  the  raw  juice  heater  to  that  at  which  it 
enters  the  evaporating  station.  This  value  is  easy  to 
find  with  the  help  of  Table  2,  page  13,  or,  more  exactly., 
according  to  the  formula: 

B  X  0.301  +  (IPO  -  B)  ^  (IOQ  +  D)  (tl  -  0 

/\ 
100  970 

wherein  B  is  the  degree  Brix;  100  +  D,  the  quantity  of 
juice  from  100  pounds  of  beets;  t  and  tl,  the  initial  and 
final  temperatures. 

(B)  The  loss  of  heat  through  radiation,  in  the  satura- 
tion tanks,  the  scum  presses,  filters  and  piping  on  the 
way  from  the  raw  juice  heater  to  the  first  body  of  the 
evaporators.      This   loss   is,   with   surfaces   sufficiently 
insulated  with  felt,  equal  on  an  average  to  a  cooling 
off  of  the  juice  of  from  about  45  degrees  to  54  degrees, 
corresponding  to  an  average  steam  consumption  of  5.5% 
(5346  B.t.u.'s).     Naturally  this  temperature  drop,  with 
its  corresponding  loss,  can  be  ascertained  through  spe- 
cial investigation  for  each  given  case,  and  from  this  the 
steam   consumption   can   be   determined  according    to 
Table  2. 

(C)  The  heating  of  the  milk  of  lime  from  the  initial 
temperature  to  the  final  temperature  of  the  juice,  which 


1 8  STEAM    ECONOMY 

is  on  an  average  about  135  degrees.  Each  pound  of  lime 
requires  on  an  average  four  pounds  of -water,  which  is 
introduced  partly  directly  into  the  lime  milk,  and  partly, 
as  sweet  water,  into  the  juice.  With  a  heat  capacity  of 
0.2  in  the  lime  there  is  required  for  each  pound  of  lime 

(IX  0.2) +(4  Xi)  x         =  Q  S84  pounds  steam 

97° 

If  the  lime  treatment  be  effected  with  unslacked  lime 
and  the  sweetening  off  with  warm  water,  then  the 

corresponding  steam  consumption  is  only **• 

97° 

=  0.027  Per  pound  of  lime,  and,  therefore,  0.584  — 
0.027  =  0.557  pounds  of  steam  per  pound  of  lime  is 
saved. 

(D)  The  heating  of  the  saturation  gas  from  an  aver- 
age of  68  degrees,  at  which  temperature  it  flows  into  the 
saturation  tank  at  atmospheric  pressure,  up  to  the  final 
temperature  at  which  it  leaves  the  juice.  With  a  heat 
capacity  of  the  gas  of  0.23  the  steam  consumption  here- 
tofore mentioned  as  necessary  for  each  pound  of  CaO  is 
determined  by  multiplying  the  corresponding  values  of 

line  5,  Table  3,  by  — -•>  where  t  is  the  final  tem- 

perature of  the  gas.  *  The  small  degree  of  moisture,  in 
the  gas  entering  the  juices,  has  here  been,  and  will  further 
be,  neglected.  The  following  Table  4  gives  the  loss  of 
, steam  with  reference  to  one  pound  CaO. 


STEAM    CONSUMPTION    OF   INDIVIDUAL    STATIONS    19 

TABLE  4. 

Steam  Consumption  in  Pounds  for  Each  Pound  of  Lime  Due  to 
Heating  of  the  Gas. 


Carbonic  acid  content  of  the  gas  (volumetric)  

15 

20 

25 

30 

1167° 

0.185 

0.123 

0.092 

0.073 

Average  final  temperature  of 
the  gas 

176° 
185° 
194° 

O.2OI 

0.218 

0-235 

0.134 
0.145 
0.156 

O.IOO 

0.108 
o.  117 

0.080 
O.OS; 
0.093 

203° 

0.251 

0.168 

0.126 

O.IOO 

(E)   Evaporation  of  the  water  in  the  saturations. 

This  is  one  of  the  main  items  of  steam  consumption  in 
the  saturation  and  also  causes  very  often  a  considerable 
loss  of  steam  in  the  factory,  which  is  proved  by  the  clouds 
of  steam  escaping  from  the  discharge  pipes  of  the  satura- 
tion tanks. 

Strange  as  it  may  seem,  this  consumption,  up  .to  date, 
has  not  been  considered.  The  values  on  lines  9  and  13 
of  Table  3  give  the  volumes  of  gas  which  leave  the  satura- 
tion under  the  various  conditions.  These  volumes  are 
saturated  with  steam. 

In  accordance  with  known  physical  laws,  the  gases 
saturated  with  steam  contain  exactly  as  much  steam 
as  would  be  contained  in  the  same  volume  at  the  same 
temperature  were  no  gas  present. 

For  the  steam  content  of  a  cubic  foot  at  varying  tem- 
peratures, there  are  existing  tables,  e.g.,  Zeuner's 
improved  table  found  in  most  of  the  handbooks.  By 
multiplying  the  values  in  this  table  by  the  corresponding 
figures  of  lines  9  to  13,  of  Table  3,  the  steam  contents 


20 


STEAM    ECONOMY 


of  the  escaping  gas  for  each  pound  CaO  is  found.  Inas- 
much as  we  leave  out  of  consideration  the.  small  quantity 
of  steam  which  was  contained  in  the  original  gas,  we 
can  say  that  this  steam  was  evaporated  out  of  the  juice. 
But,  since  for  this  evaporation  almost  exactly  as  much 
steam  must  be  condensed  in  the  heating  arrangements 
of  the  saturation,  if  no  radiation  were  to  take  place,  then 
the  resulting  figure  gives  directly  the  steam  consumption 
sought  to  be  determined  through  them.  These  figures 
are  contained  in  Table  5. 

TABLE  5. 

Steam  Consumption  Due  to  Evaporation  in  the  Saturation  for  Each 
i  %  CaO  on  the  Weight  of  Beets 


Temperature  of 

Volumetric  contents  of  the  saturation  gas  in  per  cent  COj. 

the  escaping 

gases  and 

steam. 

15% 

20% 

25% 

30% 

I67° 

2.58 

1.62 

1.  14 

0.86 

I76° 

3-70 

2.32 

1.64 

1.23 

I85° 

5-60 

3-53 

2.48 

1.86 

194° 

9-49 

S-96 

4.20 

3-i5 

203° 

21.39 

13-45 

9.46 

7.11 

(F)  Besides  the  heat  consumption  there  is  also  a  heat 
production  in  the  saturation  because  in  forming  CaC03, 
chemical  energy  is  transformed  into  heat.  On  that 
account  two  cases  must  be  distinguished : 

(1)  The  use  of  milk  of  lime,  and 

(2)  The  use  of  dry  lime. 

(i)   According  to  Thomsen,  for  each  mole-pound  of 


STEAM    CONSUMPTION    OF   INDIVIDUAL    STATIONS    21 

CaC03,  which  is  formed  from  the  aqueous  solution  of 
the  Ca(HO)2  and  CO2,  33,318  B.t.u.'s  are  liberated, 
i  per  cent  CaO  (molecular  weight  56)  corresponds  to 

33'31    =  594.96  heat  units,  which  correspond  to  a  sav- 
ing of  steam  of     594'9<5     =  0.61%. 
970  X  ioo 

(2)  According  to  Thomsen  out  of  every  mole-pound  of 
CaC03,  which  is  formed  from  dry  CaO  and  C02,  76,482 
heat  units  are  liberated,  i  per  cent  CaO  corresponds 

then  to  — — —  =  1365.7  heat  units,  equivalent  to  a  sav- 
56 

ing  of  steam  of  —         —  =  1.42%. 
970  X  ioo 

The  defecation  with    dry  lime    then   saves    1.42  - 
0.6 1  =  0.8 1%  steam  on  the  weight  of  beets  for  each  i% 
CaO,  which  saving  is  not  taken  into  account  under 
item  C. 

By  reason  of  the  heat  losses  and  the  sources  of  heat 
transference  A,  B,  C,  D,  E  and  F,  thus  far  investigated, 
it  is  easy  to  calculate  the  steam  consumption  of  the 
saturations  for  every  condition  by  adding  the  correspond- 
ing items,  calculated  or  taken  from  the  tables,  for  A,  B, 
C,  D,  E,  and  subtracting  the  value  of  F  therefrom. 
Now,  since  the  items  C,  D,  E  and  F  stand  in  direct  pro- 
portion to  the  lime  consumption,  then  in  the  following 
Table  6  (for  the  sake  of  facilitating  the  calculation)  the 
sum  of  the  items  C,  D  and  E  less  F  is  given  for  every  i% 
CaO  where  milk  of  lime  is  used.  With  dry  lime  the 
corresponding  figures  are  diminished  by  0.8 1%  in  item 


22 


STEAM    ECONOMY 


F,  and  frequently  also  by  a  further  0.55%  in  item  C, 
thus  in  total  0.81  +  0.55  =  1.36%. 

The  values  corresponding  to  the  contents  of  CO2  of 
15%,  20%,  25%  and  30%  are  computed,  the  others  are 
to  be  found  by  interpolation. 


TABLE  6. 

Steam  Consumption  in  Pounds  for  the  Items  C  +  D  +  E  —  F,  for 
Each  i%  CaO  as  Milk  of  Lime. 


tempera- 

Volumetric content  of  the  saturation  gas  in  per  cent  CO2. 

ture  of 

the  escap- 

ing gases 
and  steam. 

14 

IS 

16 

17 

18 

19 

20 

21 

22 

23 

167°..-. 

3.10 

2.73 

2.47 

2.24 

2-O.S 

1.88 

I.7I 

i-59 

I.48 

1-38 

I76°.... 

4.30 

3.87 

3-44 

3-14 

2.88 

2.64 

2.42 

2.24 

2.09 

i-95 

185°-... 

6.40 

5-79 

5-22 

4-74 

4.33 

3-97 

3-64 

3-37 

3-15 

2.94 

IQ4°.... 

II  .OO 

9.69 

8-75 

7-95 

7.20 

6-59 

6.O9 

5-65 

5  •  25 

4.90 

203°.... 

24.00 

21  .6l 

19-35 

17.60 

16.00 

14.80 

13-59 

12.50 

n.6c 

10.80 

Average 
tempera- 

Volumetric content  of  the  saturation  gas  in  per  cent  CO2. 

ture  of 

the  escap- 

ing gases 
and  steam. 

24 

25 

26 

27 

28 

29 

30 

31 

32 

167°.... 

1.28 

I  .20 

I  .  12 

i.  06 

i  .00 

o-95 

0.90 

0.85 

0.81 

I76°.... 

1.82 

I.7I 

I.  60 

1-51 

1.42 

1-35 

1.28 

I  .  21 

i-i5 

i85°.-.. 

2.74 

2.56 

2  .40 

2.26 

2.13 

2.  O2 

1.92 

1.83 

i-75 

194°..-. 

4.58 

4.29 

4-05 

3.8i 

3-60 

3-40 

3-21 

3-°4 

2.87 

203°...- 

IO.IO 

9-55 

9.OO 

8.45 

8.00 

7-55 

7.18 

6.85 

6-55 

For  the  determination  of  the  heating  surfaces  the 
heat  consumption  in  heat  units  which  is  contained  in 
the  following  table  7  is  to  be  taken  into  account. 


STEAM    CONSUMPTION   OF   INDIVIDUAL    STATIONS    23 


TABLE   7. 

Heat  Consumption  for  Items  C  +  D  +  E  —  F,  for  Each  i  %  CaO  as 
Milk  of  Lime  in  B.t.u.'s. 


Average 
temper- 
ature of 
the  es- 
caping 
gases 
and 
steam, 
°F. 

Volumetric  content  of  the  saturation  gas  in  per  cent  CO2. 

14 

15 

16 

i? 

18 

19 

20 

21 

I67° 
I76° 

I85° 
194° 
203° 

3,004 
4,180 
6,210 
10,680 
23,320 

2,660 
3,760 
5,620 
9,420 
20,990 

2,400 
3,338 
5,070 
8,510 
18,790 

2,180 
3,050 
4,610 
7,720 
17,100 

1990 
2800 
4210 
6980 
1554 

1,826 
2,565 
3,790 
6,400 
14,380 

i,  660 
2,350 
3,538 
5,920 
13,200 

i,547 
2,180 
3,278 
5,425 
12,140 

Average 
temper- 
ature of 
the  es- 
caping 
gases 
and 
steam, 

o  p> 

Volumetric  content  of  the  saturation  gas  in  per  cent  CO2. 

22 

23 

24 

25 

26 

27 

28 

29 

925 
1312 
1964 
3300 
7330 

30 

875 
1243 
1865 
3120 
6970 

31 

8277 
H75 
1778 
2958 
6485 

32 

786 
ms 

1702 

2790 
6360 

I67° 
I76° 
I85° 
I94° 
203° 

1,438 
2,030 
3,060 
5,090 
II,27O 

1,342 
1,896 
2,860 
4,760 
10,490 

1242 
1769 
2665 

445° 
9820 

1167 
1644 
2490 
4170 
9280 

1089 
1555 
2330 
3940 
8750 

1030 
1467 

2195 
3690 

8220 

973 
1380 
2070 
35oo 
7780 

We  can  now  figure  the  loss  for  the  steam  consumption 
in  the  saturations  occasioned  by  settling  the  foam  with 
steam,  as  is  the  custom  in  many  factories.  This  method 
of  breaking  the  foam  is  effective  but  much  too  costly 
and  irrational,  due  to  the  enormous  losses  of  steam 
frequently  occurring  at  this  point,  which  are  entirely 
Incalculable,  —  as  they  can  vary  in  the  widest  degree 


24  STEAM   ECONOMY 

in  one  and  the  same  establishment  according  to  the 
manipulation,  —  so  this  item  will  not  be  taken  into 
consideration. 

This  is  merely  mentioned  because  if  through  no  other 
agency,  the  foam  can  be  as  well  beaten  down  with  satu- 
ration gas. 

EXAMPLE  2. —  There  is  drawn  off  120%  of  juice  heated  to 
iy6°F.  Let  the  addition  of  lime,  in  the  form  of  milk  of  lime, 
he  3%;  the  saturation  gas  contains  24%  CO2.  Let  the  average 
temperature  of  the  saturation  be  185°  F.;  the  escaping  gases  have 
an  average  temperature  of  iy6°F.  and  the  finished  juice  enters 
into  the  evaporating  system  at  203°  F.  How  much  steam  is 
consumed  on  the  way  from  the  heater  to  the  evaporators? 

(A)  The  heating  of  the  juice  amounts  to  203°  —  176°  =  27°. 
In  accordance  with  Table  2,  the  steam  consumption  for  the  heat- 
ing of  juice  at  120%  draw  through  20°  equals  2.22%,  through  70°, 
equals   7.79%,  for  7°,  then,  0.779%  and  for  27°,   2.22  +  0.779 

3-0% 

(B)  According  to  the  previous  assumption  ....       5-5% 
C  +  D  +  E  -  F,  as  per  Table  6,  amount  to 

1.82%  for  each  i%  CaO  with  3%  lime,  then  they 

amount  to  1.82  X  3 5-46% 

Total  on  the  weight  of  the  beets  13.96%* 

For  the  sake  of  ascertaining  quickly  the  steam  con- 
sumption in  the  saturation,  under  average  conditions 
of  work,  the  following  Table  8  is  given. 

*  For  the  determination  of  the  heating  surfaces  of  the  several  stations 
of  the  saturation,  the  calculations  must  be  made  for  each  separately, 
for  which  purpose  the  preceding  values  give  sufficient  data.  On  account 
of  the  diversity  of  method  of  operation,  only  the  total  consumption  is 
given  here. 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    25 


TABLE   8. 

Steam  consumption  for  the  saturation  with  a  temperature 
difference  of  18°  F.  between  the  juice  coming  from  the  heaters 
and  that  entering  the  evaporators,  with  an  average  temperature 
of  the  escaping  gases  of  176°  F.;  120%  draw  of  juice  and  the  use 
of  milk  of  lime. 


Lime 

j     The  saturation  gas  contains  per  cent  CO2  by  volume. 

tion. 

14 

IS 

16 

17 

18 

19 

2O 

21 

22 

23 

2.0% 

16.10 

15.24 

14.38 

13-78 

13.26 

12.78 

12.34 

11.98 

11.68 

11.40 

2-5% 

18.25 

17.17 

16.10 

15-35 

14.70 

14.  10 

13-55 

13.10 

12.72 

12.37 

3-o% 

20.40 

19.11 

17.82 

16.92 

16.  14 

15-42 

14.76 

14.22 

13-77 

13-35 

3-5% 

22-55 

21  .04 

iQ-54 

18.49 

17-58 

16.74 

15-97 

15-34 

14.82 

I4-32 

4-0% 

24.70 

22.98 

21.26 

20.06 

19.02 

18.06 

I7.I8 

16.46 

15.86 

I5-30 

4-5% 

26.85 

24.91 

22.98 

21.63 

20.42 

19.38 

18.39 

17.58 

16.90 

16.27 

Lime 

The  saturation  gas  contains  per  cent  CO2  by  volume. 

tion. 

24 

25 

26 

27 

28 

29 

30 

31 

32 

2-0% 

II  .14 

10.92 

10.70 

10.52 

10.34 

IO.2O 

10.06 

9.92 

9.80 

2-5% 

12.05 

11.77 

11.50 

11.25 

11.05 

10.87 

10.70 

10.52 

10.37 

3-o% 

I2.Q6 

12.63 

12.30 

11.03 

ii  .76 

n-55 

11-34 

11.13 

IO-95 

3.5% 

13.87 

13.48 

13.10 

12.78 

12.47 

12.22 

11.98 

n-73 

11.52 

4-0% 

14.78 

13-34 

13.90 

13-54 

13.18 

I2.9O 

12.62 

12.34 

12.10 

4-5% 

15.69 

15.20 

14.70 

14.29 

13.89 

13-57 

13.26 

12.95!  12.68 

Tables  4  to  8  give  the  following  general  results. 

(i)  For  the  reduction  of  the  steam  consumption  it  is 
important  to  have  the  carbonic  acid  content  of  the  gas 
as  high  as  possible,  because  with  a  constant  amount  of 
3%  lime  at  176°  the  temperature  of  the  escaping  gases 


26  STEAM    ECONOMY 

equals  a  difference  of  1.3%  for  volumetric  contents 
between  25%  and  30%  CO2;  3.4%  between  20%  and 
30%  and  7.8%  between  15%  and  30%.  The  taking  of 
the  gas  from  the  rear  of  wood-fired  boilers  is  handy, 
but  the  advantages  of  the  lime  kiln  lie  in  the  lower  steam 
consumption.- 

(2)  The  heat  consumption  rises  with  the  addition  of 
lime.     With  a  saturation  gas  of  25%  and  an  escaping 
gas  of  176°,  the  difference  for  the  addition  of  i%  lime 
brings  about  a  difference  in  steam  consumption  of  1.7%; 
with  20%  of  2.4%;  with  15%  of  4.3%. 

Therefore,  in  view  of  the  common  acceptance,  that  a 
little  more  lime  does  not  cost  much,  and,  on  this  account, 
it  is  not  customary  to  be  economical  with  this  item,  we 
should  also  exercise  control  in  this  direction  by  means  of 
calculation.  As  a  general  thing,  it  is  advisable  to  use 
every  means  to  reduce  the  consumption  of  lime  as  much 
as  possible.  To  such  belongs  the  heating  of  the  juice  to 
at  least  185°  before  the  addition  of  the  lime,  as  also  the 
endeavor  to  keep  the  juice  as  free  from  pulp  as  possible, 
for  which  purpose  its  nitration  through  gravel,  coke,  or 
coal  screenings  would  not  prove  too  costly. 

(3)  The   steam  consumption  increases   rapidly  with 
the  temperature  of  the  escaping  gases  and  also  with  the 
temperature  of  the  juices  during  saturation.     Thus  the 
increase  from  176°  to  194°  with  3%  lime  and  a  25% 
saturation  gas   amounts  to  an  increase  in  steam  con- 
sumption of  (4.29  -  1.71)3  =  17-74%,  with  15%  C02 
of  (9.69  -  3.87)3  =  17.46%. 

For  that  reason,  from  the  viewpoint  of  steam  con- 


STEAM    CONSUMPTION   OF    INDIVIDUAL    STATIONS     27 

sumption,  it  is  also  important  to  keep  the  temperature 
of  saturation  as  low  as  possible  (just  to  the  point  that 
the  presses  will  run  well)  and  to  do  the  boiling  only  after 
final  saturation. 

Oftentimes  this  does  not  suffice,  as,  for  instance,  with 
frozen  beets,  after  stoppage  of  the  battery  or  the  re- 
introduction  of  caramelized  green  syrups,  etc.,  it  becomes 
necessary  to  boil  with  lime;  then  the  advantages  and 
disadvantages  of  these  methods  of  operation  must  be 
taken  into  account. 

If  there  be  no  special  station  for  the  separate  treat- 
ment of  the  green  syrup  and  wash  syrup  which  on 
account  of  their  reintroduction  into  the  process  should 
always  be  heated  up  with  lime,  then  the  temperature 
during  the  saturation  of  the  thin  juice  must  be  increased. 
It  is  here  that  steam  is  uselessly  wasted,  and  for  this 
reason  the  separate  treatment  of  these  products  is  very 
rational.  This  question  solves  itself  very  easily  and 
rather  judiciously  by  separate  boilings  of  these  prod- 
ucts with  lime  before  their  introduction  into  the 
saturation,  in  which  case  with  normal  beets  there  is 
no  necessity  for  boiling  until  the  termination  of  all 
saturations. 

NOTE.  —  In  the  foregoing  heat  balance  the  introductions  of 
wash  syrup  and  green  syrup  into  the  thin  juice  saturation  are  not 
considered,  because  they  usually  reach  this  station  already  heated 
and  the  steam  has,  therefore,  been  expended  at  another  point. 
If  their  temperature  be  lower  than  that  of  the  juice  entering  the 
evaporators,  this  fact  must  naturally  be  taken  into  account, 


28  STEAM    ECONOMY 

EXAMPLE  3.  —  Four  per  cent  of  green 'syrup  of  70°  Brix  and 
5%  wash  syrup  of  the  same  density  and  of  a  temperature  54  de- 
grees lower  than  that  of  the  juice  are  brought  back  into  the 
saturation  before  evaporation.  As  the  heat  capacity  of  a  strong 
solution  of  about  70°  Brix  is  0.51,  then  the  steam  consumption  is: 

(4+5)0.51X54  y 

ioo  X  970 
IV.    SULPHURATION. 

On  account  of  the  small  quantity  of  lime  which  is 
neutralized  by  the  SO2  (if  its  use  be  considered  at  all 
necessary),  there  is  no  reason  to  make  a  separate  heat 
calculation  for  this  operation.  Should  this  be  desired, 
then  we  can  assume,  that  for  the  sulphuring  to  the  neu- 
tral point  of  a  given  quantity  of  lime  the  volume  of  gas 
necessary  is  equal  approximately  to  that  of  carbonic 
acid  gas  of  15%.  For  this  special  case  the  values 
determined  can  be  taken  into  account. 

V.  THE  STEAMING  OFF  OF  THE  FILTER  PRESSES. 

The  steam  consumption  is  at  this  point  in  direct  pro- 
portion to  the  amount  of  lime  added,  if  the  filter  presses 
are  steamed  off.  Usually  there  is  obtained  4%  cake  for 
each  i%  lime.  The  steaming  off  is  carried  on  until  the 
steam  appears  at  the  outlets,  which  occurs  when  the 
cake  and  the  inner  cast-iron  parts  of  the  press  are  heated 
to  212  degrees.  For  each  i%  lime,  on  an  average,  about 
20%  of  cast  iron  must  be  heated.  If  we  assume  the  tem- 
perature of  the  juice  and  of  the  iron  before  steaming  off 
as  equal  to  176°,  the  heat  capacity  of  the  cake  0.7,  that  of 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    29 

the  cast  iron  0.13,  then  the  steam  consumption  for  each 
i%  lime  is  equal  to 

(4  X  0.7  +  20  Xo.is)  (212  -  176)  =02% 
100  X  970 

with  a  loss  on  liberation  to  atmosphere  of  about  0.25%. 
Many,  for  good  reasons,  do  not  steam  off,  and  save 
this  steam. 

VI.  THE  EVAPORATION. 
A.   The  Steam  Consumption  for  Heating  the  Juice. 

The  quantity  Q%  of  Juice>  figured  on  the  weight  of 
beets  entering  into  the  evaporation  at  B°  Brix,  is  here, 
before  it  begins  to  boil,  heated  from  its  initial  tempera- 
ture /0  to  its  boiling  temperature  t.  For  this  purpose, 
each  100  pounds  of  beets  with  a  heat  capacity  0.3  of  the 
dry  substance  of  the  juice  requires  the  application  of  heat  : 


Q(t-  /o)  I0°  ~  °'7B  heat  units.       .     .     (6) 


or 

100 


According  to  the  existing  conditions  in  the  first  body 
of  the  evaporators,  the  corresponding  heat  consumption 
will  then  be  about  954  heat  units  for  each  pound  of  steam, 


Q(t  —  tQ)  (100  -  0.7  B) 

or  —  L  —  '  per  cent    ...     (7) 

100  X  954 

The  value  of  Q  is  made  up  of  the  following  parts  : 
First:   Of  the  juice  which  is  drawn  from  the  diffusion 
(100  +£>). 


30  STEAM    ECONOMY 

Second:  Of  the  water,  which  enters  the  juice  with  the 
lime  and  as  sweetening-off  water,  corresponding  to  about 
four  times  the  quantity  of  lime  added. 

Third:  The  green  syrup  and  the  raw  sugar  of  the 
second  product  reintroduced  in  the  process. 

From  these  totals  should  be  subtracted: 

First:  The  water  evaporated  during  saturation,  which 
we  will  here  designate  by  V,  and  which  can  be  taken 
from  Table  5  for  each  i%  CaO;  and 

Second:  The  sugar  and  nonsugar  which  remain  in  the 
press-cake  and  which  amount  to  about  i%. 

If  these  figures,  together  with  the  Brix  content  of 
the  juice  and  its  temperature  before  and  in  the  first 
body,  be  known,  then  the  steam  consumption  for  this 
purpose  is  easily  determined. 

EXAMPLE  4.  —  The  draw  of  juice  is  120%;  the  addition  of 
lime  3%;  the  saturation  gas  contains  25%  CO2;  the  average 
temperature  of  the  escaping  gas  is  176  degrees,  the  introduction 
of  raw  sugar  amounts  to  3.5%;  the  green  syrup  4%;  the  juice 
is  17°  Brix,  and  enters  the  first  body  with  a  temperature  lower 
by  21.6  degrees  than  that  existing  therein. 

According  to  Table  5,  V  =  164  X  3  =  4-92%; 

Q  =  120  +  (4  X  3)  +  3-5  +  4  -  4-92  -  i  =  133-6%, 
from  which  the  steam  consumption 

133.6X21.6(100-0.7  Xi7)  = 
100  X  954 

Hereafter  this  steam  consumption  will  be  considered 
entirely  separate  from  that  which  is  used  for  the  evapora- 
tion proper. 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    31 

For  rough  calculation  use  can  be  made  of  Table  2, 
estimating  approximately  the  quantity  of  juice  or 
measuring  it  directly. 

EXAMPLE  5.  —  Again  assume  the  temperature  difference  to  be 
21.6°  and  the  quantity  of  juice  entering  the  evaporators  130%,, 
then,  according  to  Table  2,  the  steam  consumption  for  20  degrees  = 
2.41%,  for  1.6°  =  0.19%,  then  for  21.6°  =  2.41  +  0.19  =  2.60%.. 

B.   Steam  Consumption  j or  the  Evaporation  Proper. 

The  quantity  of  water  which  is  eliminated  in  the 
evaporating  station  is  equal  to  the  difference  between 
the  entering  thin  juice  and  the  outgoing  thick  juice,  but. 
as  ordinarily  neither  the  one  nor  the  other  is  regularly 
measured,  this  value  must  be  determined  indirectly 
from  the  estimated  quantity  of  thin  juice  and  the  Brix 
content  before  and  after  evaporation. 

EXAMPLE  6.  — There  is,  similarly  to  Example  4,  Q  =  133.6% 
at  17°  Brix;  the  thick  juice  is  of  60°  Brix;  then  its  quantity  is 
found  from  the  proportion  X:  Q  :  :  17  :  60,  where  X  =  133.6  X 
H  =  37-85%.  Therefore  133.6  -  37.85  =  95-75%  water  is  evap- 
orated. 

The  consumption  of  steam  for  this  purpose  depends  on : 

(1)  The  number  of  bodies. 

(2)  How  much  juice  vapor  is  utilized  for  the  purpose 

of  heating,  also  from  which  body  it  is  taken. 

(3)  The  unavoidable  losses  due  to  leaks  in  the  tubes, 

to  drawing  off  of  the  ammoniacal  vapors  and 
to  radiation. 

If  the  first  body  be  considered  separately,  it  can  be 
easily  ascertained  from  Zeuner's  table,  that,  if  the  con- 


32  STEAM    ECONOMY 

densed  water  flows  out  at  the  temperature  of  the  steam, 
one  pound  of  steam  evaporates  a  little  less  water,  but, 
if  the  condensed  water  goes  out  at  the  temperature  of 
the  juice,  then  one  pound  of  steam  evaporates  slightly 
more  water.  As  in  reality  the  temperature  of  the 
condensed  water  lies  between  these  limits,  we  can,  in 
practice,  without  committing  any  considerable  error, 
assume  that  in  the  first  body  one  pound  of  steam  evapo- 
rates an  equal  quantity  of  water. 

We  can  say  exactly  the  same  thing  relative  to  each 
following  body,  if  the  juice  entering  it  has  the  same  tem- 
perature as  that  existing  in  the  body.  But  this  is  not 
,at  all  the  case,  because  the  juice  always  comes  over  at 
the  higher  temperature  of  the  preceding  body  and,  as 
soon  as  it  reaches  the  compartment  at  a  lower  pressure, 
it  loses  this  excess  of  heat  by  the  evaporation  of  a  part 
of  its  water  content.  For  this  reason  there  will  always 
be  evaporated  more  water  in  the  following  bodies  for 
a  unit  quantity  of  steam. 

It  would  be  easy  to  figure  out  this  excess  for  any  given 
case,  but  there  are  other  factors  which  operate  in  an 
opposite  sense,  namely: 

(1)  The  losses  through  leaks  in  the  tubes. 

(2)  The  radiation. 

(3)  The  piping  for  ammoniacal  vapors;     the  steam 

which  enters  into  the  different  bodies  through 

the  connections  for  the  water  drain  traps,  etc. 

These  influences  cannot  all  be  accurately  determined. 

We  will,  therefore,  assume  that  they  all  balance;  that 

.in  each  body  a  given  quantity  of  steam  must  evaporate 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS     33. 

a  similar  quantity  of  water;  that  in  this  manner  by 
ordinary  triple  evaporation  one  pound  of  steam  evapo- 
rates three  pounds  of  water;  in  a  plain  quadruple  evapo- 
rator, one  pound  of  steam  evaporates  four  pounds  of 
water,  etc.  This  assumption  has  the  advantage  of 
simplicity  over  all  other  methods  of  calculation  without 
being  any  the  less  accurate.* 

As  previously  mentioned,  the  steam  consumption, 
besides  depending  upon  the  number  of  bodies,  depends 
also  upon  the  use  of  the  vapors  (juice)  for  the  purpose 
of  heating  according  to  the  principle  of  Rillieux,  which 
establishes  the  evaporation  from  a  line  of  p  bodies,  as 

i,  2  .  .  m  .  .  n  .  .  o  .  .  .  p, 

and  takes  out  of  m,  n  and  o  for  each  100  pounds  of 
beets  M%,  N%  and  O%  of  steam  for  the  purpose  of 
heating.  If  we  indicate  the  quantity  of  steam  which 
is  introduced  into  the  first  body  for  the  special  pur- 
pose of  evaporation  (without  preheating)  by  Xy  then,, 
according  to  what  has  been  said  before,  X  will  be 
evaporated  in  each  of  the  bodies  up  to  m  inclusive 
and  in  total  mX%  water  in  the  first  m  bodies. 

*  As  an  example  of  the  methods  of  "exact"  people,  the  following 
may  be  mentioned:  Some  time  ago,  Jelinek  calculated  the  steam 
evaporation  in  a  single  effect  at  0.9,  in  a  double  effect  at  1.96,  in  a  triple 
effect  at  2.85,  in  a  quadruple  effect  at  3.79,  and  in  a  quintuple  effect 
at  4.72,  and  this  under  assumptions  taken  at  random,  as  for  instance, 
juice  temperature  167  degrees  and  so  on.  These  figures,  taken  at  ran- 
dom, are  used  today  in  all  texts  and  manuals,  except  in  the  one  by 
Hausbrandt.  They  are  taken  as  something  universally  accepted  and 
tables  are  based  on  them.  Calculations  continue  to  be  made  according 
to  these  random  figures,  which  are  simply  worthless. 


34  STEAM    ECONOMY 

All  the  succeeding  bodies  until  n  inclusive  will  evapo- 
rate by  M%  less>  hence  (X  -  M)t  together  (X  -  M) 
(n  —  m). 

The  then  remaining  bodies  up  to  o  inclusive  evaporate 
still  less,  namely:  (X-M-N)  but  jointly  (X-M-N) 
(o  —  n).  Each  of  the  succeeding  bodies  will  then  evapo- 
rate (X-M-N-0)  and  jointly  (X-M-N-O) 
(p  —  o).  If  we  call  the  total  of  the  water  evaporated  in 
the  entire  system  5,  then 

mX  +  (n  -  m)  (X  -  M)  +  (o  -  n)  (X  -  M  -  N) 

-{-(p  -  o)  (X  -  M  -  N  -  O)  =  S, 
and 

With  this  formula  it  is  easy  to  calculate  the  steam 
necessary  for  evaporation. 

EXAMPLE  7.  —  There  is  to  be  evaporated  in  a  quintuple  effect 
96%  water;  moreover,  there  is  to  be  taken  for  different  purposes 
from  the  first  body  8%;  from  the  second  body  12%;  and  from  the 
third  body  10%  of  the  steam,  then 

m=  i;  n=  2;  o  =  3,and/>=  5; 
M  =  8;  N  =  12;  O  =  10, and-S  =  96;  and 

A--8+»+ie+o6-'x8-aX"-3X10  =  36.8%. 

EXAMPLE  8.  —  In  a  quadruple  effect,  8%  steam  is  taken  out 
of  the  second  and  third  bodies. 

S  is  here  again  96%;  andm  =2;  n  =  3;  o  =  zero;  p  =  4; 

then  ^8  +  8  +  96-2X8-3X8  = 

4 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    35 

If  the  evaporating  system  has  a  (single  effect)  Pauly 
body,  which  is  fed  with  direct  steam,  the  calculation  is 
carried  on  in  a  similar  manner,  if  the  evaporation  in 
the  Pauly  body  has  been  determined  or  estimated.  It 
is  then  only  necessary  to  make  the  total  calculation 
without  the  Pauly  body  and  to  diminish  5  by  the  amount 
of  the  evaporation  in  the  juice  boiler  y. 

If  in  the  equation  (8)  we  substitute  in  place  of  5,  the 
new  value  S  —  y,  then 

xi  =  M  +  N  +  0+S-y-mM-nN-°0.   (9) 

P 

xl  means  here  the  total  quantity  of  steam  led  into  the 
first  body  of  which  y%  comes  from  the  juice  vapors  of 
the  Pauly  body  and  (x1  —  y)%  from  the  exhaust  steam. 

But  as  the  quantity  of  juice  vapor  from  the  juice  boiler 
is  equal  to  the  quantity  of  direct  (boiler)  steam  entering 
it  (the  portion  which  is  used  up  for  heating,  as  a  matter 
of  fact,  not  being  considered),  xl  is  equal  to  the  total 
consumption  of  boiler  and  exhaust  steam  used  for  the 
purpose  of  evaporation. 

EXAMPLE  9.  —  A  quadruple  effect  is  provided  with  a  juice 
boiler  which  evaporates  8%  water.  The  juice  vapor  is  taken  only 
from  the  second  body  to  the  amount  of  25%.  The  total  evapora- 
tion is  here  again  96%.  How  much  steam  is  used  ? 

In  the  equation  (9) 

M  =  25;  m  =  2;  n  and  o  =  zero  and  p  =  4, 

then  «.  -  25  +  «*-8-'X»S  -  34-5%, 

4 

of  which  8%  comes  in  the  form  of  direct  steam  for  utilization  in 
the  juice  boiler  and  34.5  —  8  =  26.5%  as  (return)  exhaust  steam 
in  the  first  body  (mixed  with  8%  vapor  from  the  juice  boiler). 


36  STEAM    ECONOMY 

VII.  THE  BOILING. 

The  quantity  of  water  evaporated  in  boiling  is  deter- 
mined in  the  same  manner  as  that  in  the  evaporation 
station. 

EXAMPLE  10.  —  From  37.85%  of  thick  juice  of  60°  Brix  (ac- 
cording to  Example  6)  there  is  obtained  (without  the  addition 
of  the  second  product  before  dropping)  a  fillmass  of  94°  Brix  and 
from  an  undetermined  quantity  of  second  product  of  78°  Brix, 
7%  of  fiUmass  of  second  product  at  03°  Brix.  How  much  total 
water  is  evaporated? 

There  is  obtained        37.85  X  f f  =  24.16% 

of  first  product  fillmass, 
therefore,  there  is  evaporated  37-85  —  24.16  =13.69% 

water  while  boiling  the  same. 
There  must  be  present  7  X  f  f  =  8.35% 

of  raw  second  product,  from 
which  there  must  be  evaporated,  out 

of  the  second  product,  as  water  8.3  5  —  7         =   1.35% 

together  then  15.04% 

The  steam  consumption  is  dependent  upon  the  tem- 
perature of  the  steam,  of  the  condensed  water  and  upon 
other  conditions. 

If  the  temperatures  of  the  thick  juice  and  of  the  syrup 
entering  the  vacuum  pan  are  equal  to  the  temperature 
of  the  finished  fillmass,  and  the  condensed  water  goes 
out  at  the  original  temperature  of  the  steam,  then  the 
steam  consumption  with  a  steam  pressure  of 

o        7.5       15       21.5       30        45        60  pounds  per  square  inch 
is    1.04     1.05     1.07     1.08     1.09     i.io     1. 12  pounds 

for  each  pound  of  water  evaporated. 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    37 

If  the  temperature  of  the  condensed  water  is  lower, 
the  steam  consumption  is  lower  than  mentioned.  For 
instance,  if,  in  a  vacuum  pan  fitted  with  serpentine  coils, 
the  steam  pressure,  at  the  conclusion  of  the  strike,  falls 
from  60  to  30  pounds  per  square  inch,  corresponding  to 
a  decrease  in  temperature  of  307.3°  to  274°,  then  the 
steam  consumption  for  each  pound  of  evaporated  water 
is  only  1.08  pounds  instead  of  1.12.  But  as  there  is  in 
every  type  of  vacuum  pan  during  certain  periods  of  the 
boiling  a  small  loss  of  heat  through  the  piping  for 
the  drain  traps,  this  increase  in  utilization  on  account 
of  the  drop  in  temperature  need  not  be  further  con- 
sidered. 

In  addition  a  certain  quantity  of  steam  is  used  for 
steaming  off  the  vacuum  pans  after  dropping  the  strike. 
This  quantity  cannot  be  calculated  and  varies  in  widely 
differing  limits  according  to  the  water  content  of  the 
mass  and  the  design  of  the  vacuum  pan. 

EXAMPLE  n.  —  For  the  evaporation  of  15.04%  of  water  (see 
Example  10)  out  of  the  first  and  second  products,  there  is  required, 
at  a  steam  pressure  of  45  pounds  per  square  inch,  15.04  X  1.1  = 
16.54%  steam;  with  the  steaming  off  and  reevaporation  of  the 
water  so  introduced,  about  17%. 

VIII.  THE  HEATING  OF  THE  THICK  JUICE  AND  SYRUPS. 

The  thick  juice  before  filtration  and  the  syrup,  which 
is  boiled  for  the  second  product,  are  usually  heated, 
as  are  also  the  syrups  of  second  and  third  products, 
which  are  intended  for  the  dilution  of  the  next  higher 
fillmasses. 


38  STEAM    ECONOMY 

The  steam  consumption  connected  'therewith  can  be 
easily  determined  according  to  one  of  the  previously 
described  methods. 

EXAMPLE  12.  — There  is  37.85%  thick  juice  of  60°  Brix  (Ex- 
amples 6  and  10)  to  be  heated  through  54  degrees;  8.35%  of 
syrup  of  second  product  of  78°  Brix  (Example  10)  to  be  heated 
through  72  degrees  and  about  3%  syrup  of  second  and  third  prod- 
ucts of  78°  Brix,  which  are  to  be  utilized  for  dilution,  to  be  heated 
through  72  degrees. 

The  heat  capacity  at  60°  Brix  =  0.58,  at  78°  Brix  =  0.45. 
Therefore,  the  steam  consumption  is,  when  for  each  pound  954 
B.t.u.'s  are  used, 

37.85  X  0.58  X  54  +  (8.35  +  3)  Q-45  X  72          ,  ~ 
954 

IX.  THE   TREATMENT   OF   THE    GREEN   SYRUPS   AND 
THE  REMELTED  PRODUCTS. 

Owing  to  the  multiplicity  of  methods  to  be  applied  at 
this  point,  there  can  be  given  no  general  rule  for  the 
calculation  of  the  steam  consumption. 

When  the  heating  with  lime  and  a  saturation  with 
CO2  or  862  exists,  then  the  calculation  may  be  carried 
on  in  the  same  manner  as  for  the  saturation  of  the  thin 
juice,  and  the  tables  there  given  hold  true  when  the 
lime  consumption  is  considered  in  relation  to  the  weight 
of  the  beets. 

EXAMPLE  13.  —  3.5%  of  raw  sugar  of  second  product  at  86° 
and  4%  of  the  higher  purity  green  of  78°  Brix  and  122°  F.  are  dis- 
solved with  about  60%  juice  of  176  degrees,  and  then  boiled  with 
lime. 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    39 

Since  0.9,  0.45  and  0.3  are  the  heat  capacities  of  the  juice, 
syrup  and  sugar,  then  the  steam  consumption  is 

3-  5x0.3(212  -86)  +  4x0.45(212  -122)  +(3.5  +  4)^x0.9(212  -176) 

954  x  100 

=  0.46%. 

If  0.1%  CaO  be  added,  in  the  form  of 
milk  of  lime,  and  heated  up  to  167  degrees, 
then  the  steam  consumption  in  addition 
to  this  is,  according  to  item  C  058  _  ,~ 

10      — — — 
a  total  of     0.52%. 

EXAMPLE  14.  —  Under  the  conditions  adduced  in  Example  13, 
with  a  subsequent  addition  of  carbonic  acid  of  25%,  0.1%  of  lime 
on  the  weight  of  the  beets  is  fully  saturated  at  an  average  tem- 
perature of  the  escaping  gas  of  194  degrees. 

Row  much  steam  is  used  by  this  saturation? 

According  to  Table  6  the  steam  consumption  for  items 
C  +  D  +  E-F  for  each  i%  CaO  =  4.29  for  0.1%  CaO,  then 

4-iH9  _  0.43%,  including  the  heating  up  of  the  milk  of  lime;  with- 
10 

out  this  last  mentioned  heating  0.43  —  0.06  =  0.37%. 

For  both  operations,  according  to  Examples  13  and  14,  then 
0.52  +  0.37  =  0.89%. 


X.    THE   TURBINATING  AND   WASHING. 

Here  the  steam  consumption  varies  within  wide  limits 
from  0.5%  to  1.5%  on  the  weight  of  the  beets,  according 
to  the  type  of  centrifugals,  their  equipment  and  the 
method  of  working. 

In  reality  the  consumption  ought  to  be  restricted  to 
the  dislodging  of  the  air  from  the  centrifugal  and  to  the 
heating  of  the  sugar  and  the  centrifugal.  If  the  centrif- 


40  STEAM   ECONOMY 

ugals  were  hermetically  closed,  then  indeed  would  such 
be  the  case.  The  same  steam  would  then  be  made  to  re- 
enter  into  circulation  over  the  upper  free  space  of  the 
centrifugal  (after  the  sugar  and  the  centrifugal  had  been 
warmed  up)  by  means  of  the  centrifugal  force  exerted 
from  the  inside  of  the  centrifugal  through  the  layer  of 
sugar  in  the  basket.  In  reality  the  steam  runs  out  into 
the  atmosphere  in  greater  quantities  through  the  drain 
spouts,  and  also  through  the  open  bottom  in  the  curb 
of  the  Weston  centrifugals.  For  the  most  part,  one  does 
not  content  himself  with  these  losses  and  arranges  the 
centrifugal  casings,  with  special  drain  pipes  of  large 
dimensions,  in  the  erroneous  expectation  of  thereby 
accelerating  the  operation  and  being  less  importuned  by 
the  steam.  The  result  is  clear;  the  greater  the  volume 
of  steam  induced  by  this  circulation,  the  more  steam 
must  be  introduced  through  the  steam  valve.  If  not, 
the  cold  outer  air  will  force  its  way  into  the  centrifugal, 
thereby  retarding  the  work  considerably. 

If  there  be  affixed  to  the  outlet  spouts  of  the  centrifugal 
simple  hydraulic  locking  devices  or  very  light  valves 
(which  are  opened  by  the  discharge),  or  proper  covers 
on  the  inner  side  of  the  inlet  opening,  which  divert  the 
whirl  of  the  steam  from  this  outlet,  then  this  loss  of 
steam  can  be  brought  to  amount  to  nil.  It  is 
more  difficult  to  close  the  lower  opening  of  a  Weston 
centrifugal,  although  this  can  be  done  by  means  of  special 
lift  valves. 

With  such  apparatus  and  with  the  closing  of  the  ven- 
tilating pipes,  success  has  been  obtained  in  accelerating 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    41 

the  work  and  in  diminishing  the  steam  and  the  heat 
in  the  working  spaces,  and  at  the  same  time,  in  reduc- 
ing the  steam  consumption  to  about  half. 

The  ventilation  of  the  centrifugal  is  of  use  only  while 
emptying,  as  the  operator  will  not  then  be  inconvenienced 
by  the  rising  steam. 

This  is  accomplished  by  means  of  special  throttle 
valves,  which  are  set  in  the  discharge  pipes  and  are 
opened  while  the  lid  is  raised. 

The  encasing  of  the  centrifugal  basket  serves  the  same 
purpose  and  also  serves  for  the  economizing  of  steam,  and 
this  happens  contrary  to  the  erroneous  idea  that  the  con- 
densation of  the  steam  in  the  basket  does  not  have  any 
influence  on  the  steam  consumption. 

From  the  above  it  is  clear,  without  further  proof,  that 
just  as  much  steam  as  will  be  here  condensed  must  be 
introduced  through  the  steam  valve. 

XI.   STEAM  LOSSES  DUE  TO  RADIATION. 

According  to  Claassen  this  loss  of  steam  in  the  boiler 
and  exhaust  lines  with  a  fair  insulation  for  an  elaboration 
of  770  tons  of  beets  amounts  to  2.49%,  and  in  the  steam 
cylinders  to  0.26%. 

The  losses  incidental  to  the  diffusion  (from  0.5%  to 
i%)  and  to  the  saturations  with  the  coincident  nitra- 
tions (about  5.5%)  have  already  been  taken  into  account 
under  the  individual  stations. 

It  is  estimated  that  the  loss  of  steam  in  the  evapora- 
tors and  vacuum  pans  through  radiation  is  1.5%,  on  an 
average.  The  heating  of  the  thick  juice  and  of  the 


42  STEAM    ECONOMY 

syrups  which  also  occasion  partial  losses  by  cooling  have 
already  been  taken  into  calculation.  Wherefore,  the 
losses  of  steam  through  radiation  not  taken  into  account 
in  the  preceding  chapters  amount  together  to 


2.49  +  0.26  +  1.50  =  4.25 


oy 
/o- 


This  last  figure  gives,  in  conjunction  with  the  losses 
previously  taken  into  account  in  the  diffusion  (from  0.5% 
to  i%)  and  in  the  saturations  with  nitrations  (about 
5.5%)  and  others,  a  total  loss  through  radiation  of  from 
10%  to  12%  on  the  weight  of  beets,  which  is  sufficiently 
large  to  be  given  weighty  consideration.  With  very 
good  insulation  of  all  pipe  connections  and  fittings,  this 
loss  can  be  diminished;  with  inadequate  insulation,  it 
can  be  further  increased. 

For  the  purpose  of  judging  the  relative  value  of 
different  materials  of  insulation,  the  conclusions  of 
Rietschel's  researches  are  very  instructive. 

For  our  purpose  they  are  given  again,  rather  con- 
verted and  somewhat  condensed,  in  the  following  Table  9. 

For  the  determination  of  the  value  of  new  materials 
for  insulation,  one  can  be  guided  by  the  very  simple 
and  comprehensive  references  of  Ordway,  namely,  the 
lower  the  weight  of  a  given  volume  of  the  heat  protecting 
medium,  the  greater  is  the  heat  protection. 

Table  9  shows  that  cheap  felt  is  the  best  heat  pro- 
tecting medium.  It  has  only  one  drawback,  namely, 
that  for  high  pressure  steam,  it  cannot  be  applied  directly 
on  the  piping. 

For  this  purpose,  Babcock  &  Wilcox  recommend  the 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    43 


TABLE  9. 
i  i 

Heat  Loss  if  the  Loss  with  Noninsulated  Surface  be  Taken  =  100. 


Kind  of  covering. 

Thickness  of  the  layer  of 
covering. 

inch. 

.§f 
inch. 

I 
inch. 

•    ^ 

inches. 

Strands  of  straw  covered  with  clay  .  .  . 
Wrapping  of  asbestos  yarn  with  asbes- 
tos fibre  

69 

59 
46 

38 
44 
25 
25 

19 

64 

56 
42 

33 
35 

22 
22 

16 

60 

54 
40 

30 
29 
20 
2O 

14 

57 

52 
39 

28 
24 
19 
19 

13 

Different  preparations  of  Kieselguhr  .  . 
Various  kinds  of  artificial  cement  prep- 
arations   
Cork  shavings  
Silk  braids  without  air  space  
Carbonized  silk  

Felt,  soft  brown  material  without  cov- 
ering, or  covered  and  saturated  with 
a  solution  of  dextrine 

wrapping  with  asbestos  millboard,  over  which,  according 
to  the  diameter  of  the  pipes,  from  6  to  1 2  wooden  staves 
are  laid  and  fastened  with  wire.  Over  this  skeleton  un- 
tarred  millboard  is  wrapped  and  properly  fastened.  At 
the  flanges,  the  spaces  between  the  staves  are  blocked 
with  wood  and  the  interstices  for  the  bolts  subsequently 
packed  with  felt.  An  envelope  of  sheet  tin  with  a 
covering  of  felt  over  it  would  give  the  same  or  better 
service. 

The  following  table  (10)  gives  approximately  the  heat 
and  steam  losses  for  unprotected  wrought  or  cast-iron 
surfaces.  With  copper  the  corresponding  values  are 
about  one- third  lower. 


44 


STEAM    ECONOMY 


TABLE 


10. 


Loss  per  Hour  through  Radiation  for  i  Square  Foot  of  Wrought- 
or  Cast-iron  Surfaces. 


Temperature 
differences, 
°P. 

B.t.u's. 

Steam  in 
pounds. 

18 

33-2 

0-°35 

36 

66.4 

0.070 

54 

107.0 

0.113 

72 

147-8 

o.  156 

90 

IQ9-5 

0.  211 

108 

251 

O.266 

126 

302.5 

0.320 

144 

362 

0.383 

162 

421 

0-445 

180 

480 

0.508 

198 

535 

0.566 

216 

609 

0.645 

234 

683 

0.723 

252 

746 

0.789 

270 

823 

0.871 

288 

905 

0-957 

306 

990 

1.048 

In  order  to  ascertain  the  heat  or  steam  loss  per  square 
foot  for  this  or  that  class  of  covering  it  is  sufficient  to 
multiply  the  figures  given  in  Table  10  by  the  correspond- 
ing values  in  Table  9,  and  then  divide  by  100. 

Naturally  much  depends  upon  how  the  insulation  is 
applied.  For  instance,  an  ordinarily  beautiful  looking 
lagging  with  an  air  space  underneath  may  sometimes 
produce  harm  instead  of  the  desired  advantage,  as  the 
circulation  of  the  air  induced  thereby  may  bring  about 
an  increase  in  heat  transference.  From  this  point  of 
view,  the  felt  covering  with  a  thin  sheet  of  iron  over  it 
is  more  rational. 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    45 

XII.   THE  MECHANICAL  WORK. 

On  an  average  it  can  be  assumed  that  for  an  hourly 
working  of  100  pounds  of  beets  0.67  to  0.82  I.H.P.  or 
0.55  to  0.67  E.H.P.  are  necessary. 

The  steam  consumption  necessary  for  one  I.H.P.  can 
be  approximately  taken  from  Table  n. 

For  the  effective  H.P.  the  steam  consumption  is  about 
15%  higher.  Naturally  this  table  cannot  have  any  very 
great  claim  to  accuracy  in  every  special  case,  as  the  con- 
dition of  the  machinery  plays  an  important  part. 

Ordinarily  the  hourly  steam  consumption  varies  for  an 
indicated  H.P.  within  limits  between  30  and  60  pounds 
and  between  25  and  54%  on  the  weight  of  the  beets. 

However  large  this  steam  consumption  may  be,  in 
every  average  factory  the  total  exhaust  steam  will  be 
utilized.  Therefore,  the  steam  consumption  necessary 
for  the  production  of  the  mechanical  work  is  not  any 
larger  than  its  theoretically  determined  value,  i.e.,  one 
B.t.u.  develops  778  foot  pounds  of  work. 

The  losses  of  steam  incidental  to  the  operation  of  the 
machinery  due  to  radiation  in  the  piping,  connections 
and  steam  cylinders,  have  already  been  taken  into  con- 
sideration in  the  previous  chapter. 

The  consumption  of   heat  for  one  H.P.  hour  (=  550 

r  j    .  jx  550  X  60  X  60 

foot  pounds  in  one  second)  amounts  to  ^— 

778 

=  2545  B.t.u. 's  for  0.67  to  0.82  I.H.P.  or  1705  to  2080 
B.t.u.'s  per  100  pounds  of  beets.  Since  this  heat  is 
liberated  through  condensation  and  as  one  pound  of 


g>      R8$3 


a   I 


w 


«? 

1 

^ 

f 


6% 


Tf  ICO  t- 

6666 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    47 

steam  of  an  average  of  970  B.t.u.'s,  according  to  the 
conditions  existing  in  the  steam  cylinders,  is  liberated, 
the  steam  used  up  for  the  performance  of  the  mechani- 
cal work  amounts  then  to  from  -*-*  to =  1.75  to 

970          970 

2.14%  on  the  weight  of  beets. 

On  this  point  the  determinations  of  different  authors 
vary  widely,  according  to  the  views  each  one  has  as 
regards  the  somewhat  complex  thermodynamic  process 
which  takes  place  in  a  steam  engine. 

Jelinek  estimated,  without  reason,  the  steam  which  is 
condensed,  when  passing  through  the  steam  engines,  as 
30%  of  the  steam  entering.  A  great  number  of  others 
fell  into  the  error  of  assuming  a  special  loss  of  steam 
due  to  its  expansion  beyond  the  steam  cylinder,  and  the 
larger,  the  greater  the  cut-off  of  the  engine.  In  this 
they  overlooked  the  fact  that  steam  expanding  into  the 
heating  spaces  performs  no  external  work  as  would  be 
the  case  were  the  exhaust  steam  to  pass  off  into  the 
atmosphere. 

In  reality  there  exists  here,  besides  those  already 
determined,  no  further  loss  of  steam;  for,  if  we  consider 
an  installation  of  machinery,  joined  to  a  system  of  heat- 
ing arrangements,  as  a  whole,  we  will  have  here  only 
steam  or  heat  consumption: 

i.  For  the  performance  of  the  mechanical  work  in- 
clusive of  the  friction  losses  in  the  machinery  itself, 
which  amount  is  given  by  the  indicator,  and  2.  For 
the  radiation.  There  can  be  no  further  heat  losses. 


48  STEAM   ECONOMY 

Since  the  best  steam-condensing  engine  of  suitable 
dimensions  (in  a  sugar  factory)  requires  1 2  to  15  pounds 
of  steam  per  I.H.P.,  or  about  10%  on  the  weight  of 
beets,  it  is  plain  that  the  very  best  condensing  engine 
does  not  stand  comparison  with  the  ordinary  type  of 
engine,  whose  exhaust  (steam)  is  utilized,  as  the  latter 
consumes  only  1.75  to  2.14%,  and  thus  saves  about  8% 
over  the  former. 

As  the  calculated  steam  consumption  of  1.75  to 
2.14%  does  not  depend  in  any  way  on  the  good  quality 
of  the  engines,  it  follows  that  as  long  as  a  rational  utili- 
zation of  the  exhaust  steam  is  possible,  the  number  and 
quality  of  the  steam  engines  have  no  influence  over 
the  total  steam  consumption,  naturally  not  taking  into 
consideration  the  difference  in  the  dimensions  of  the 
radiating  surfaces  which  can  only  amount  to  a  fraction 
of  a  per  cent. 

It  is  almost  superfluous  to  mention  that  all  devices 
for  the  superheating  of  steam  in  a  sugar  factory  are  only 
of  a  very  restricted  value,  as  the  heat  and  steam  con- 
sumption for  the  performance  of  the  mechanical  work 
and  for  purposes  of  heating  and  boiling  would  not 
thereby  be  changed. 

If  the  steam  consumption  of  the  engines  is  diminished, 
a  proportionally  greater  amount  of  direct  steam  would 
have  to  be  introduced  into  the  evaporators. 

If  both  high  and  low  pressure  boiler  steam  be  utilized, 
the  only  logical  result  is  that  while  the  utilization  of  high 
pressure  steam  decreases,  the  demand  for  low  pressure 
steam  increases  correspondingly. 


STEAM    CONSUMPTION    OF    INDIVIDUAL    STATIONS    49 

In  one  case  one  set  of  boilers  is  relieved;  in  the  other 
case  it  is  taxed  that  much  more. 

The  recent  attempt  to  discover  an  advantage  in  the 
adoption  of  superheating,  because  the  superheated 
steam  gives  off  less  heat  in  the  piping,  is  more  theoretical 
than  real,  since  this  economy  would  never  amount  to 
i%  on  the  weight  of  the  beets.  For  that  reason,  to 
install  a  superheater  is  surely  to  follow  the  wrong  course, 
since  there  is  a  possibility,  in  every  factory,  to  make 
more  remunerative  improvements  for  the  same  money. 

The  only  advantage  in  superheating  arrangements  and 
modern  improved  engines  lies  in  the  smaller  quantity  of 
exhaust  steam  which  they  produce. 

The  smaller  the  quantity  of  exhaust  steam,  the  greater 
the  field  for  a  system  of  utilization  of  the  juice  vapors, 
to  which  reference  will  be  made  later. 

XIII.  OTHER  STEAM  CONSUMING  STATIONS. 

Besides  the  stations  previously  mentioned,  there  can 
also  be  other  places  where  steam  is  used,  such  as  bone- 
black  houses  and  filtration,  molasses  desugarizing  proc- 
esses, heating  and  ventilation  of  buildings,  etc. 

The  quantity  used  in  each  case  must  be  determined 
according  to  special  requirements. 

We  will  not  concern  ourselves  further  with  these 
processes  which  are  becoming  rarer  from  day  to  day. 

The  steam  consumption  for  the  Steffens  separation  is 
frequently  estimated  as  15%  of  the  total  steam  con- 
sumption of  the  factory. 


THE   DISTRIBUTION    OF   STEAM   IN   THE 
FACTORY. 

I.  METHODS  FOR  REDUCTION  OF  THE  TOTAL 
STEAM   CONSUMPTION. 

Tip  to  the  present  we  have  treated  of  the  steam  con- 
sumption of  the  individual  stations  and  of  the  causes 
influencing  it. 

Now,  we  will  endeavor  to  give  a  general  view  of  the 
ways  and  means,  which,  independently  of  the  steam  con- 
sumption of  the  individual  stations,  have  for  their  purpose 
the  reduction  of  the  total  consumption  of  boiler  steam. 

As  a  first  means  of  this  kind  stands  the  process  of  the 
multiple  utilization  of  the  latent  heat  of  steam,  first 
proposed  by  Rillieux,  of  which  we  have  already  made 
some  mention  under  the  discussion  of  evaporation. 

As  there  worked  out,  we  established  that,  if  the  quan- 
tity of  water  S  is  to  be  evaporated  out  of  the  juice, 

this  can  be  effected  by  means  of  manifold  evaporation 

£ 
in  a  number  of  bodies  />,  with  an  expenditure  of  only  — 

of  steam. 

A  second  not  less  important  process,  also  brought 
into  practice  by  Rillieux  (the  so-called  "  second  Rillieux 
principle"),  consists  in  substituting  in  the  several  heating 
and  boiling  stations  vapors  from  one  of  the  evaporating 
bodies  in  lieu  of  boiler  and  exhaust  steam. 

5° 


DISTRIBUTION   OF    STEAM    IN   THE    FACTORY       51 

Let  us  now  fully  investigate  what  advantage  the 
application  of  this  second  principle  can  offer  in  each 
individual  case. 

Again  assume  a  system  of  evaporation  of  any  given 
number  of  bodies, 

i,  2  ...  m  ...  n  ...  o  ...  p, 

out  of  which  a  total  of  S  pounds  of  water  is  to  be  evap- 
orated. 

The  arrangement  is  such  as  to  permit  of  taking  out 
of  the  bodies  m,  n  and  o,  M,  N  and  O  pounds  of  vapors 
for  utilization  in  different  stations  of  the  factory. 

If  no  use  be  made  of  this  arrangement,   then,   as 

previously  stated,  there  must  be  applied  to  the  evapora- 

§ 
tion  —  and  to  the  other  stations  (M  +  N  +  O)  pounds 

of  steam;  therefore,  in  the  system  under  consideration  a 
total  of  (-  +  M  +  N  +  0\  pounds. 

On  the  other  hand,  according  to  equation  (8),  page 
34,  the  total  steam  consumption  by  the  application  of 
Rillieux's  principle  is 


P 

therefore,  the  economy  of  steam  resulting  from  the 
application  of  this  principle  is  equal  to  the  difference 
between  these  two  totals,  i.e., 


or,  by  solving          mM  +  nN  +  °°  .  (10) 


52 


STEAM  ECONOMY 


This  theorem  establishes  the  fact  that  the  economy  of 
steam  through  the  utilization  of  juice  vapors  is  equal  to 
the  sum  of  the  vapors  taken  from  each  body,  multi- 
plied by  the  number  indicating  its  position  in  the  series, 
divided  by  the  number  of  bodies  in  the  system. 

EXAMPLE  15.  — In  a  quadruple  effect  there  will  be  taken  from 
the  first  body  (for  vacuum  pan  and  saturation)  16%,  from  the 
second  body  (for  diffusion  and  heaters)  14%  and  from  the  fourth 
body  (for  heaters)  3%. 

Then  m  =  i,  n  =  2,  o  =  4,  M,  N,  (^respectively  =  16,  14  and 
3,  and  p  =  4,  and  the  economy  of  steam  is 

i  X  16  +  2  X  14  +  4  X  3          ~ 

4X100 

Were  the  abstraction  of  the  vapors  the  reverse,  viz.,  from  the 
first  body  3%,  from  the  second  14%  and  from  the  fourth  16%, 
then  the  economy  resulting  would  be 


Table  12  gives  a  synopsis  of  the  total  steam  economy 
to  be  secured  for  each  body  by  the  utilization  of  vapors 
from  the  evaporators. 

TABLE   12. 

The  "  Second  Principle  of  Rillieux  "  gives  the  Total  Steam  Sav- 
ing in  per  cent  of  the  Consumption  in  the  Stations  heated 
with  Juice  Vapors. 


Evaporating 

system. 

I 

II 

III 

IV 

V 

VI 

Single 

IOO 

Double 

c;o 

IOO 

Triple 

•2-2      •3'} 

66  66 

IOO 

Quadruple 

2C 

CQ 

ye 

IOO 

Quintuple  

20 

40 

60 

80 

IOO 

Sextuple  

16.66 

33-33 

50 

66.66 

83.33 

IOO 

DISTRIBUTION   OF    STEAM    IN   THE    FACTORY        53 

This  table  makes  it  possible,  also,  to  calculate  the 
economy  for  each  case. 

In  the  case  of  Example  15,  the  economy  in  the  first 

body  would  be  16  X  —  -  ,  in  the  second  14  X  -**  —  •,  and  in 
100  100 


TOO  2  C 

the  fourth  3  X  -  -  ;   together,  16  X  —  +  14  X 


TOO  2  C  CO 

-  -  ;   together,  16  X  —  +  14  X  — 

100  100  IOO 


If  for  the  evaporation  there  be  utilized  boiler  steam 
besides  exhaust,  the  modification  of  the  principle  of 
Rillieux,  proposed  by  Pauly,  consists  in  not  introducing 
it  (boiler  steam)  directly  into  the  first  body,  but  into  a 
special  juice  boiler  or  so-called  0  body,  Pauly  or  boiler, 
the  vapors  from  which  together  with  the  exhaust  steam 
are  led  into  the  first  body  and  thus  used  once  more. 

The  saving  in  steam,  which  the  installation  of  a  juice 
boiler  can  bring  about,  is  equal  to  the  difference  between 
the  use  of  direct  and  exhaust  steam  for  both  cases  (with 
and  without  a  Pauly  or  juice  boiler)  as  is  shown,  in  a 
general  way,  in  equations  (8)  and  (9),  pages  34  and  35. 

By  subtracting  the  values  in  equation  (9)  from  those 
in  equation  (8),  we  find  the  required  steam  saving, 
namely  : 

,-*:-Z. 

p 

Therefore,  an  0  body  or  Pauly  economizes  such  a 
portion  of  the  direct  steam  introduced  into  it,  as  there 
are  bodies  in  the  evaporating  system,  to  which  it  is 
connected. 


54  STEAM  ECONOMY 

EXAMPLE  16.  —  A  quadruple  effect  receives,  in  addition  to 
exhaust  steam,  10%  of  direct  steam.  Later  a  Pauly,  which 
received  only  8%  of  direct  steam,  was  connected  to  this  system; 

0 

then  a  saving  of  -  =  2%  was  effected. 
4 

A  peculiar  method  of  utilizing  juice  vapors  consists 
in  compressing  a  part  of  the  vapors  coming  out  of  any 
one  body  and  introducing  the  same  into  the  first  body. 
This  principle  was  first  recommended  by  Koerting  and 
it  was  intended  that  this  compression  should  be  effected 
by  an  injector  fed  with  high-pressure  steam. 

Later  Weibel  proposed  to  accomplish  this  by  means 
of  special  piston-actuated  compressors,  which  had  some 
justification  only  where  a  sufficient  quantity  of  mechani- 
cal power  was  gratuitously  obtainable. 

Like  the  Pauly  system,  this  method  can  be  applied 
only  when  the  condition  of  the  steam  engines  makes  it 
necessary  to  furnish  the  first  body  continuously  with  an 
adequate  quantity  of  direct  steam.  As  a  representative 
of  the  firm  of  Koerting  Brothers  stated  to  Dr.  Claassen, 
there  are  required  about  2  pounds  of  boiler  steam  at 
90  pounds  per  square  inch  for  the  compression  of  i  pound 
of  juice  vapor  from  10.5  to  22.5  pounds  per  square  inch. 

The  economy  to  be  thereby  secured  can  be  ascertained 
from  Table  12.  For  example,  if  the  vapor  be  taken  from 
the  second  body  of  a  quadruple  effecf,  then  one  econo- 
mizes 50%  of  the  vapors  taken  out,  etc. 

EXAMPLE  17.  —  Let  us  again  take  the  case  of  Example  16. 
Conditions  there  are  such  as  to  make  it  possible  to  give  to  the 
first  body  of  a  quadruple  effect  10%  of  direct  steam.  If  it  is 
desired,  in  lieu  of  this,  to  use  a  mixture  of  one  part  vapor  from  the 


DISTRIBUTION    OF    STEAM    IN    THE    FACTORY        55 

second  body  and  two  parts  of  live  steam  (from  the  boilers),  then 

there  is  obtained  for  —  =  3.33%  juice  vapors,  2  X  —  =  6.66% 

3  o 

direct  (boiler)  steam.    Now  since  the  vapor  taken  from  the  second 
body  (according  to  Table  12)  economizes  50%  of  its  weight,  then 

the  economy  amounts  to  3.33  X  -* —  =  1.66%. 

100 

A  comparison  of  this  result  with  the  economy  (2%), 
which  we  figured  in  Example  16,  for  the  Pauly,  shows 
that  the  latter  affords  greater  advantages. 

The  result  would  hardly  vary  in  favor  of  compression 
if  the  vapors  were  taken  from  the  third  body  in  lieu  of 
the  second,  as  then  the  compression  of  one  pound  of 
vapor  (juice),  owing  to  its  correspondingly  decreased 
pressure,  would  require  much  more  direct  boiler  steam. 

If  there  is  taken  into  account  the  fact  that  an  injector 
always  requires  the  flow  of  the  full  quantity  of  direct 
steam  (as  otherwise,  instead  of  sending  juice  vapors  into 
the  second  body,  direct  steam  could  easily  be  introduced) 
and  that  the  evaporation  is  of  necessity  subject  to 
variations,  one  arrives  at  the  conclusion  that  the  real 
value  of  the  apparently  attractive  process  is  very  slight. 

II.  THE  PRACTICAL  ADAPTABILITY  OF  THE  DIFFERENT 
SYSTEMS  FOR  UTILIZING  JUICE  VAPORS. 

Having  explained  the  theory  of  the  different  systems 
which  have  for  their  purpose  the  total  steam  economy,  we 
will  proceed  to  the  investigation  of  the  practical  adapta- 
tion of  these  principles.  But  before  going  further  into 
the  matter,  we  will  first  tabulate  the  steam  consumption 


56  STEAM  ECONOMY 

of  the  separate  stations  under  average  operating  c6n- 
ditions,  as  we  have  already  partly  introduced  them  in 
the  examples.  This  is  done  in  the  following  table. 

TABLE   13. 

Average  steam  consumption  with  120%  draw  (of  juice);  heating 
of  the  raw  juice  from  95  to  iSfr0;  an  average  temperature  of  176° 
of  the  saturation  gas  with  3%  of  lime  in  the  form  of  milk  of  lime; 
25%  saturation  gas,  and  other  conditions  as  below  outlined. 

1 .  Diffusion  (average) 7 . 00% 

2.  Heating  of  the  raw  juice 10.00 

3.  Saturation  of   the    thin  juice    (according   to 

Tables) 12.63 

4.  Steaming  of  the  filter  presses .75 

5.  Heating  of  the  juice  to  the  boiling  point  in  the 

first  body  (Example  4,  page  30) 2.66 

6.  Evaporation  of  96%  water  (similarly  to  Exam- 

ple 6)  in  a  quadruple  effect 24.00 

7.  Boiling  to  grain  (Example  n,  page  37) 17.00 

8.  Heating  of  the  thick  juice  and  of  the  syrups 

(Example  12,  page  38) i  .63 

9.  Treatment  of  the  green  syrup  and  wash  syrup 

(Examples  13,  14,  pages  38  and  39) 0.89 

10.  Turbinating i .  oo 

11.  Radiation 4. 25 

12.  Mechanical  work 2 .00 

Total  with  a  complete  utilization  of  the  exhaust 
steam 83.81% 

By  the  use  of  a  triple  effect  the  steam  consumption 
necessary  for  evaporation,  instead  of  24,  would  have  been 

^—  =  32%,  with  a  double  effect  ^-  =  48%  and  the  total 

steam  consumption  as  above  would  have  been,  respec- 
tively, 91.82%  and  107.82%. 


DISTRIBUTION    OF    STEAM    IN    THE    FACTORY        57 

Through  the  incomplete  utilization  of  the  exhaust 
steam  there  arises  a  corresponding  demand,  which  would 
also  be  greater  in  the  case  of  thick  juice  of  lower  density 
and  of  other  variations,  increasing  the  steam  consump- 
tion of  the  individual  stations. 

With  all  possible  combinations  of  steam  distribution 
which  have  for  purpose  the  diminishing  of  the  total 
steam  consumption  above  calculated,  we  must  always 
have  in  view  the  temperatures  up  to  which  the  heating 
must  be  brought,  as  also  the  temperatures  of  the  steams 
with  which  this  is  to  be  accomplished,  for  we  can  only 
heat  with  advantage  if  a  minimum  temperature  differ- 
ence of  about  1 8°  is  obtainable. 

The  higher  the  temperature  of  the  vapors  in  the  sev- 
eral evaporating  bodies,  the  wider  is  the  field  of  their 
adaptability;  the  higher  the  temperature  to  which  the 
heating  must  be  carried,  the  higher  must  be  the  pressure 
of  the  steam  entering  into  use. 

As  the  economy  of  steam  is  greater  in  proportion  to 
the  stages  of  evaporation  through  which  the  heating 
steam  has  already  passed  before  its  utilization,  the  diffi- 
culties to  be  contended  with  in  the  utilization  of  the  juice 
vapors  are  clearly  to  be  seen. 

In  order  to  push  the  economy  of  the  total  steam  as  far 
as  possible  it  is  necessary: 

First:  To  so  construct  the  several  heating  devices 
that  they  can  attain  their  purpose  with  the  least  possible 
temperature  difference,  for  which  one  employs  the  largest 
possible  heating  surfaces,  to  accelerate  the  circulation 
of  the  juices  to  the  utmost,  especially  close  to  the  heating 


58  STEAM  ECONOMY 

surfaces;  to  offer  the  greatest  cross  section  to  the 
(heating)  steam;  to  replace  heating  coils  by  bundles 
of  tubes,  etc. 

Second :  The  temperatures  in  the  first,  second  and 
occasionally  also  in  the  third  body,  as  long  as  the  pos- 
sibility of  caramelizing  does  not  dictate  otherwise,  must 
be  kept  as  high  as  possible,  achieved  by  enlarging  the 
first  body  at  the  expense  of  the  last,  provided  this  is 
not  accompanied  by  a  too  costly  enlargement  of  the 
entire  plant. 

As  Claassen  has  proved  by  experiment,  it  is  profitable, 
in  order  to  have  the  total  heating  surface  as  small  as 
possible,  to  have  the  heating  surface  in  tjie  first  body  as 
large  as  possible  in  comparison  with  the  last.  Latterly, 
Willaime  has  sought  to  demonstrate  that  this  was  not 
the  case  to  the  extent  stated  by  Claassen. 

Even  if  the  last  claim  had  a  slight  justification, 
Claassen's  conclusions  remain  authoritative  for  practice, 
for,  in  the  first  place,  the  field  for  the  employment  of  the 
vapors  is  greater  and,  in  the  second  place,  it  follows 
that  the  calorizators,  heaters,  etc.,  which  are  heated  with 
juice  vapors  may  be  made  correspondingly  smaller. 

In  spite  of  all  of  these  considerations  the  task  of  the 
rational  arrangement  for  evaporating  and  heating  be- 
comes very  complicated. 

On  the  one  hand,  greater  steam  economy  must  be 
sought;  on  the  other  hand,  other  extremes,  such  as  sugar 
losses  and  the  amortization  of  too  costly  investments 
which  can  overstep  the  economies  in  fuel,  should  be 
avoided. 


DISTRIBUTION    OF    STEAM    IN    THE    FACTORY       59 

A  formula  which  embraces  the  mathematical  relation 
between  all  these  factors  —  including  the  price  of  fuel, 
sugar  and  heating  surfaces  —  has  not  yet  been  given 
and  we  will  not  concern  ourselves  with  it,  as  ultimately 
we  would  surely  be  lacking  some  coefficients. 

We  will  restrict  ourselves  to  the  consideration  of  a  few 
general  points  of  view,  which  will  at  least  permit  us  to 
avoid  more  serious  errors. 

To  this  end,  we  will  first  investigate  which  maximum 
temperatures  we  can  have  at  our  disposal  in  the  individ- 
ual bodies,  in  order  to  determine  their  utilization  at  the 
separate  stations. 

III.   THE  DISTRIBUTION  OF  TEMPERATURE  IN 
THE  EVAPORATING  SYSTEM. 

The  density  of  the  juice  in  the  different  bodies  will 
first  be  determined,  and  for  this  purpose  let  us  turn 
back  to  Example  6,  which  conforms  to  the  average  con- 
ditions of  operations  that  have  been  under  considera- 
tion. Assume  that  the  juice  enters  into  the  evaporation 
at  17°  Brix  and  leaves  it  at  60°  Brix.  As  will  be  seen 
further  on,  in  a  factory  with  extensive  application  of 
vapors,  more  than  40%  of  the  total  evaporation  occurs 
in  the  first  body  of  a  quadruple  effect;  with  a  juice 
boiler,  inclusive  of  the  same,  up  to  about  50%;  in  the 
second  body  about  35  to  40%,  and  the  remaining  10% 
to  20%  are  divided  between  the  third  and  fourth  bodies. 
Simple  calculation  shows  that  with  such  a  distribution 
the  density  of  the  juice  in  the  first  body  will  be  about 


60  STEAM  ECONOMY 

25°  Brix,  in  the  second  body  about  45°  Brix,  in  the 
third  body  50°  Brix  and  in  the  fourth  body  60°  Brix. 

As  is  well  known,  the  boiling  temperature  increases 
with  the  density  of  the  juice.  Thus,  with  juice  at  25° 
Brix,  this  temperature  is  only  about  i°  higher  than  the 
boiling  temperature  of  water;  at  45°  Brix  this  difference 
amounts  to  only  3.2°;  at  50°  Brix  to  4°  and  finally  at 
60°  Brix  to  about  6.3°. 

The  temperature  of  the  vapor  rising  out  of  the  liquid 
will  not  be  influenced  at  all  by  this  increase;  it  always 
remains  equal  to  the  boiling  temperature  of  water 
corresponding  to  the  then  existing  steam  pressure. 

The  figures  mentioned,  i°,  3.2°,  4°  and  6.3°,  are  entirely 
useless  losses  of  heat  which  are  occasioned  by  the  tem- 
perature difference  between  the  boiling  juices  and  the 
vapors  escaping  therefrom.  This  difference  will  be  in- 
creased by  the  influence  of  the  head  of  juice  above  the 
heating  surface. 

As  everyone  knows,  the  vapors  which  form  from  the 
liquid  at  a  given  height  must  have  an  increased  tension 
due  to  the  pressure  from  the  column  of  the  liquid,  and 
thus  a  correspondingly  higher  temperature  than  at  the 
heating  surfaces.  In  order  to  make  possible  the  creation 
of  the  vapor  the  liquid  must  be  heated  up  that  much 
more  at  the  heating  surface. 

For  this  drop  in  heat  this  temperature  difference  is 
also  unprofitably  expended. 

This  loss  increases  with  the  vacuum  independently  of 
the  column  of  juice  and  its  density.  For  example,  with 
an  average  head  of  juice  of  12  inches  in  the  first  and 


DISTRIBUTION  OF   STEAM  IN  THE   FACTORY        6 1 

second  bodies,  corresponding  to  a  head  of  water  of  13 
and  14  inches  respectively,  at  a  pressure  which  differs 
little  from  that  of  the  atmosphere,  this  loss  is  about  i  .8° ; 
in  the  third  body,  corresponding  to  a  head  of  water  of 
15  inches,  at  a  temperature  of  167  to  176°,  this  loss  is 
3.6°;  and  in  the  fourth  body,  with  15.5  inches  and  60° 
Brix,  this  loss  is  about  7.2°. 

As  another  cause  for  this  drop  in  heat,  we  must  con- 
sider also  the  friction  in  the  connections,  juice  catchers 
and  heating  chambers;  and  lastly,  as  a  fourth  cause,  the 
loss  of  pressure  which  arises  especially  in  the  final  piping 
of  the  last  bodies,  because  the  temperature  of  the  vapor 
does  not  exactly  correspond  to  the  pressure,  which  is 
indicated  by  the  vacuum  gauge  as  existing,  since  there 
is  mixed  with  the  vapor  at  this  point  a  certain  quantity 
of  uncondensable  gases,  against  which  a  part  of  the 
pressure  is  exerted.  The  real  tension  of  the  vapor  and 
its  corresponding  temperature  are  therefore  somewhat 
lower. 

The  loss  in  temperature  dependent  upon  these  two 
conditions  cannot  be  correctly  estimated  and  probably 
amounts  on  an  average  to  less  than  1.8°  for  each  body. 

In  this  manner  the  total  loss  in  the  first  body  amounts 
to  about  4.5°,  in  the  second  to  7.2°,  in  the  third  to  9°, 
in  the  fourth  to  between  14°  and  16°,  and  in  total  to 
about  36°  for  all  four  bodies. 

After  this  explanation,  the  work  of  each  body  individu- 
ally will  be  considered. 

Juice  Boiler.  —  The  high  temperature  of  the  boiler 
steam  could  here  secure  practically  any  desired  tempera- 


62  STEAM  ECONOMY 

ture.  It  is  only  necessary  not  to  exceed  the  tempera- 
tures which  occasion  caramelization.  The  investigations 
of  Professor  Herzfeld  show  that  even  at  248°  the  sugar 
destruction  is  not  very  great.  If  the  juice  boiler  or 
heating  body  were  so  constructed  that  the  juice  would 
have  to  remain  in  it  only  about  one  minute,  an  objec- 
tion could  hardly  be  made  to  this  temperature. 

Unfortunately,  in  practice,  this  effort  towards  limiting 
the  juice  space  is  not  noticeable  and,  therefore,  an  effort 
is  made  to  secure  a  juice  temperature  as  far  below  240° 
as  possible. 

First  Body.  —  In  practice  one  meets  with  temperatures, 
in  the  neighborhood  of  220°  and  not  over  230°.  Owing 
to  the  large  dimensions  which  it  is  necessary  to  give  to 
the  first  body,  it  would  be  desirable  not  to  exceed  this 
last-named  temperature.  This  is  permissible  only  where 
properly  constructed  vertical  evaporating  bodies  with 
a  minimum  juice  space  are  at  hand.  With  the  usual 
horizontal  evaporating  apparatus  it  is  better  to  operate 
with  a  temperature  not  over  221  to  223°.  With  a  useful 
drop  in  temperature  of  7.2  to  9°  and  a  heat  loss  of  4.5°, 
as  calculated  by  us,  the  heating  steam  must  be  warmer 
by  11.7  to  13.5°,  which  corresponds  to  a  difference  in 
pressure  of  about  6  pounds  per  square  inch.  In  cases 
where  the  condition  of  the  engines  does  not  permit  to 
maintain  a  correspondingly  high  pressure  in  the  exhaust 
system,  the  pressure  in  the  first  body  must  naturally  be 
lowered. 

Second  Body.  —  The  resulting  temperature  of  the  juice 
vapors  in  the  second  body  depends  on  the  temperature 


DISTRIBUTION   OF    STEAM    IN   THE    FACTORY       6$ 

of  the  juice  vapors  in  the  first  body  and  the  dimensions, 
of  the  heating  surfaces  of  the  second  body. 

The  higher  the  temperature  in  the  first  body  and  the 
larger  the  heating  surface  of  the  second,  the  less  the 
difference  in  temperature  between  the  first  and  second 
and  the  higher  the  temperature  in  the  second.  Based 
on  the  investigations  of  Claassen  we  know  that  with, 
temperatures  in  the  vicinity  of  212°  a  useful  drop  in 
temperature  of  9°  still  assures  a  good  coefficient  of  heat: 
transmission. 

With  these  figures  as  a  basis,  and  by  adding  thereta 
our  estimated  temperature  loss  of  7.2°,  We  find  that  the 
temperature  difference  between  the  first  and  second 
bodies  must  not  be  kept  below  16.2°.  In  the  second 
bodies  of  evaporating  systems  constructed  for  proper 
utilization  of  juice  vapors,  one  finds  for  the  most  part 
a  pressure  of  0  or  a  low  vacuum  up  to  5.92  inches 
mercury,  with  a  temperature  of  199.4  to  212°. 

Third  Body.  —  In  this  body  the  useless  losses  in  heat 
already  reach  as  high  as  9°.  If  we  assume  with  Claassen 
the  necessity  of  maintaining  a  useful  drop  in  heat  of 
about  14.4°  here,  we  find  that  the  temperature  difference 
between  the  vapor  of  the  second  and  third  bodies  should 
not  be  less  than  23.4°.  The  temperature  in  the  third 
body  can,  therefore,  not  be  over  176  to  188.6°. 

Fourth  Body.  —  With  a  temperature  in  the  juice 
vapors  of  140°,  corresponding  to  a  vacuum  of  24  inches, 
and  our  estimated  loss  due  to  drop  in  heat  of  16.2°,  there 
remains  a  useful  drop  in  temperature  of  176°  -  (140°  + 
16.2°)  =  19.8°,  or  of  188.6°  -  (140°  +  16.2°)  =  32.4°, 


64  STEAM   ECONOMY. 

according  to  which  the  dimensions  of  the  heating  surface 
of  this  body  must  be  proportioned. 

The  preceding  considerations  have  reference  to  the 
commonly  utilized  quadruple  effect  evaporation.  For 
the  purpose  of  figuring  other  combinations  easily  and 
•correctly,  Table  14,  which  gives  general  data  as  to  the 
.approximate  losses  by  drop  in  heat  with  the  different 
number  of  bodies  is  furnished.  It  is  to  be  observed 
that  the  total  loss  (an  average  of  7.2°  for  each  body) 
increases  very  significantly  with  the  number  of  bodies. 


TABLE   14. 

Unprofitable  heat  losses  in  the  evaporating  systems  when  using 
juice  vapors  for  the  purpose  of  heating,  with  an  average  column 
of  juice  of  12  inches  above  the  heating  surface;  thick  juice  of  60° 
Brix  and  the  customary  vacuum. 


Evaporation 
system. 

Loss  in  temperature  difference,  degrees  F. 

The  individual  bodies. 

Total. 

I 

II 

III 

IV 

V 

Single  
Double  
Triple  
Quadruple.  . 
Quintuple  .  .  . 

15-3 
7.2 

5-4 

4-5 
4-5 

JS-3 
22.5 
29.7 
36 
44.1 

15-3 
9 

7.2 

5-4 

15-3 
9 
8.1 

15-3 
10.8 

15-3 

Having  ascertained  the  limits  of  temperature  of  the 
juice  vapors  with  which  we  must  deal  in  the  different 
bodies,  we  can  proceed  *o  solve  the  question  as  to  the 
steam  with  which  this- or  that  station  should  be  heated. 


DISTRIBUTION    OF    STEAM    IN    THE    FACTORY        65 

IV.  THE  LIMITS  OF  TEMPERATURE  FOR  THE  HEATING 

STATIONS  WITH  REFERENCE  TO  THE  ADAPTABILITY 

OF  JUICE  VAPORS. 

Diffusion.  —  Average  steam  consumption  7%.  The 
highest  temperature  which  is  brought  into  use  is  about 
185°;  ordinarily  177.8  or  179.6°  is  reached;  very  excep- 
tionally 1 88. 6°.  If  this  temperature  is  compared  with 
that  of  the  juice  vapor  from  the  third  body  of  a  quad- 
ruple effect,  it  is  evident  at  once  that  there  can  be  no 
argument  in  favor  of  using  the  same  here. 

It  is  most  reasonable,  therefore,  to  calculate  the 
heating  surfaces  of  the  calorizators  for  heating  from  the 
second  body,  whereby,  according  to  Table  12,  a  total 

economy  of  7  X  -*—  =  3-5%  of  steam  is  obtainable,  as 
100 

against  which  heating  from  the  first  body  would  give 
only  7   X  -  L  =  1.75%  or  exactly  half. 

In  order  to  make  possible  the  heating  of  the  diffusion 
from  the  second  body,  it  is  necessary  to  have  caloriza- 
tors of  sufficiently  large  dimensions  and  a  minimum 
temperature  difference  of  not  less  than  18°. 

Heaters.  —  Average  steam  consumption  10%.  The 
heating  is  effected  mostly  from  95  to  185°.  If  it  be 
desired  to  utilize  only  one  kind  of  heating  steam,  then 
the  heating  from  the  second  body  is  the  most  advanta- 
geous. Since  the  possibility  is  here  present  of  carrying 
on  the  heating  in  stages  through  several  units,  the  first 
heating  up  to  about  122°  can  be  effected  from  the  fourth 


66  STEAM  ECONOMY 

body  and  the  remainder  successively  from  the  third 
and  second.  Manifold  pipe  connections,  heating  units, 
water  drainage  and  fittings  are  here  necessary  and  these 
complicate  and  increase  the  cost  of  the  plant  to  such 
an  extent  that  the  advantage  gained  often  becomes 
illusory. 

The  oft-endeavored  attempt  at  successive  heating 
from  third,  second  and  first  bodies  is  unquestionably 
unprofitable,  since  the  total  of  the  benefits  to  be  so 

derived,-^— — —     — -  =  50%  only,  merely  balances  ex- 
3  X  100 

actly  that  benefit,  which  can  be  obtained  at  much  lower 
cost  and  less  trouble  by  exclusive  heating  from  the 
second  body. 

If  it  be  further  taken  into  consideration  that  the 
destruction  of  sugar,  due  to  the  bacteria  present  in  the 
diffusion  and  measuring  tanks,  increases  more  easily  in 
heaters  fed  with  vapors  from  the  fourth  body,  and  even 
occasionally  here  reach  their  extreme  limit,  and  that  at 
times  the  drainage  of  the  condensed  water  from  a  heating 
chamber  under  a  vacuum  of  from  23.8  to  25.5  inches 
does  not  always  take  place  readily,  it  will  generally  be 
discovered  that  the  exclusive  heating  from  the  second 
body  is  most  appropriate. 

Only  with  very  costly  fuel  can  it  be  recommended  to 
bring  into  use  the  succeeding  bodies. 

If  one-third  of  the  heating  were  effected  from  the 
fourth  body  and  two-thirds  from  the  second,  the  economy 

,.  .    ,     ,  100    X    I     +    50    X    2  ,,        rtf 

of  steam  then  would  be =  66.7%. 


DISTRIBUTION   OF    STEAM    IN    THE    FACTORY       67 

Were  the  heating  carried  on  in  equal  parts  from  the 
third  and  second  bodies,  the  advantage  is  almost  the 
same,  namely: 

;p 

)0 

Saturation.  —  Steam  consumption  10  to  15%.  The 
lowest  temperature  at  which  saturation  is  for  the  most 
part  carried  on  is  about  176°.  It,  therefore,  can  not 
be  heated  from  the  third  body.  On  the  other  hand, 
as  the  temperature  must  rise  up  to  194°  and  above, 
between  the  first  and  second  saturation,  and,  after  com- 
plete saturation,  up  to  212°,  there  can  also  be  no  question 
as  to  exclusive  heating  from  the  second  body. 

For  the  first  saturation,  due  to  radiation  and  also  to 
the  practice  of  heating  while  the  gas  is  being  introduced, 
and,  moreover,  owing  to  the  turbid  condition  of  the  juice 
in  the  tanks,  this  is  possible  only  with  heating  coils;  it 
appears  that  the  utilization  of  direct  steam  is  inevitable 
at  this  station. 

Therefore,  the  method  resorted  to  by  Nogaczewski, 
which  consists  in  continuously  taking  the  juice  out  of 
the  tank  while  saturating,  and  returning  it  to  the  juice 
spaces  of  the  tank  through  a  special  heater,  by  means  of 
a  centrifugal  pump,  appears  very  rational. 

For  this  purpose,  juice  vapor  can  be  used  at  will,  and 
the  foam  is  broken  down  by  means  of  the  flow  of  juice. 

As  the  heating  of  the  first  saturation  is  not  commonly 
carried  beyond  185°,  this  can  be  done  very  well  with 
vapors  from  the  second  body. 

The   heating   of    the    second   and   third   saturations 


68  STEAM  ECONOMY 

depends  too  much  upon  the  methods  of  operation 
taken  into  consideration,  which  can  be  manifold.  For 
this  reason,  it  is  not  possible,  therefore,  to  give  here 
any  definite  formula  for  the  heating.  In  general,  60  to 
70%  of  the  heat  necessary  for  saturation  can  be  taken 
from  the  second  body  according  to  Nogaczewski,  and 
the  remainder  made  up  from  the  first  body  or  in  extreme 
cases  with  direct  steam. 

For  the  most  part  the  entire  saturation  is  found  to  be 
carried  on  with  direct  steam. 

Boiling.  —  The  steam  consumption  according  to  the 
density  of  the  juice  is  here  from  16  to  20%. 

The  maximum  temperature  of  the  massecuite  during 
the  building  up  of  the  grain  is  about  185°;  only  with 
massecuites  containing  raffinose  and  with  second  prod- 
ucts does  it  now  and  then  go  higher.* 

During  the  remainder  of  the  time  the  temperature  is 
generally  lower. 

There  would  also  be  no  objection  to  use  here  the  vapors 
from  the  second  body  if  the  pressure  of  the  massecuite 
on  the  heating  surfaces  did  not  so  oppose. 

In  modern  vacuum  pans,  the  average  height  of  the 
massecuite  above  the  heating  surface  is  3  feet  at  the 
beginning  of  the  boiling  and  at  the  close  sometimes 
10  feet  high. 

With  the  density  of  the  massecuite  1.5,  this  is  equiva- 
lent to  a  pressure  of  4.5  feet  of  water  at  the  beginning 
and  15  feet  at  the  finish;  and  this  is  equal  to  a  rise  in 

*  In  a  factory  operating  with  the  Strontian  process,  I  have  seen  the 
graining  occur  at  212°. 


DISTRIBUTION   OF    STEAM    IN    THE    FACTORY        69 

absolute  pressure  of  6  inches  of  mercury  at  the  surfaces, 
and,  according  to  Fleegner's  tables,  a  rise  in  temperature 
of  21.6  to  50.4°. 

If  these  degrees  are  added  to  the  temperature  above 
mentioned,  it  is  evident  that  in  the  modern  vacuum  pans 
there  can  be  no  question  as  to  heating  from  the  second 
body,  especially  so  since  the  heating  from  the  first  body 
introduces  considerable  difficulties  and  this  conclusion  is 
also  verified  in  practice. 

In  all  modern  vacuum  pans  which  are  provided  with 
arrangements  for  heating  from  the  first  body,  the  upper 
coils  only  or  heating  drums  are  used  for  this  purpose. 

As  long  as  the  film  on  these  heating  surfaces  is  thin, 
they  will  take  up  juice  vapors  fairly  well,  although  the 
lower  sections,  partly  fed  with  direct  steam,  work  much 
more  energetically,  at  which  point  the  useful  drop  in 
temperature  is  several  times  greater. 

As  the  boiling  process  goes  on  and  the  level  of  the 
mass  over  the  heating  surface  increases,  the  temperature 
of  evaporation  next  to  the  heating  surface  rises,  and  with 
it  the  already  low  temperature  drop  of  the  upper  sur- 
faces becomes  equal  to  nothing  and  the  whole  remainder 
of  the  work  is  carried  on  with  direct  steam. 

Thus  it  happens  that  the  portion  developed  from  the 
juice  vapor  amounts  to  less  than  half  of  the  total  work 
(in  most  cases  to  only  one-quarter)  in  spite  of  the  fact 
that  the  heating  surface  for  juice  vapor  is  often  very 
large. 

But  as  the  economy  to  be  secured  by  heating  from  the 
first  body  of  a  quadruple  effect  amounts  to  only  25%, 


70  STEAM  ECONOMY 

it  follows  that  the  total  benefits  to  be  derived  amount 
at  most  to  2%,  and  very  frequently  only  to  i%  steam 
on  the  weight  of  the  beets,  which  seldom  offsets  the 
additional  expenditures  for  such  installations,  so  much 
more  so  that  the  dimensions  of  the  apparatus  and  the 
pipe  connections  increase,  and  further  losses  are  occa- 
sioned by  radiation. 

The  advantages  of  heating  from  the  second  body 
would  naturally  be  lower. 

From  this  it  is  evident  that  there  is  a  possibility  that 
apparatus  will  be  constructed  in  the  future  which  will 
boil  to  grain  by  using  juice  vapors  exclusively  from  the 
second  body,  which  would  correspond  to  an  economy 
of  steam  of  about  8%. 

V.  DIAGRAMS  FOR  THE  DISTRIBUTION  OF  STEAM. 

There  still  remains  for  us  to  give  a  few  diagrams  for 
the  distribution  of  the  steam,  which  encompass  and  elu- 
cidate our  previous  determinations. 

For  this  purpose,  we  will  turn  back  to  the  conditions 
of  operation  which  are  tabulated  in  Table  13,  page  56, 
wherein  we  will  combine  the  steam  consumption  for  the 
smaller  items  4,  5,  8,  9,  10,  n  and  12  under  one  com- 
mon figure,  13.18%. 

DIAGRAM  i .  —  A  factory  is  fitted  with  a  quadruple 
effect  and  all  stations  are  heated  with  boiler  and  exhaust 
steam. 


DISTRIBUTION    OF    STEAM    IN    THE    FACTORY       71 

Boiler  and  Exhaust  Steam 
Consumption: 

Diffusion 7 . 00% 

Heaters 10.00% 

H 

Saturation 12.63%  % 

Vacuum  pans —  17. 00% 
Sundries  (4,  5,  8, 

9,  10,  n,  12).  .  13-18%  o 

Evaporation.  . . .  24.00%*  ~">I~~1_JI~I_>III~T_>IV~)'24% 

Total 83.81% 

24         24          24  24 

Water  evaporation,  96%. 

DIAGRAM  2.  —  Diffusion  and  heaters  are  heated  from 
the  second  body  and  the  entire  remainder  with  boiler 
and  exhaust  steam. 

Boiler  and  Exhaust  Steam  d  ^ 

Consumption:  .2  t-i 

T2  .6?%  fctj    "3 

3«  I 

8 
TT  $ 


32.5     32.5       15.5       15.5 
Water  evaporation,  96%. 

*  Here,  as  in. all  the  following  diagrams,  this  figure  expresses  only 
the  steam  which  is  really  utilized  for  evaporation.  That  portion  which 
is  used  for  heating  in  the  first  body  or,  in  other  words,  as  a  juice  boiler, 
is,  according  to  line  five  of  Table  13,  included  in  the  2.66%  under  the 
heading  of  "Sundries."  This  value  must  always  be  added  to  that  given 
for  the  juice  boiler  or  for  the  first  body,  if  one  take  into  consideration 
the  steam  entering  into  either  when  calculating  the  vapor  pipes. 


Saturation  

12.63% 

Vacuum  pans  .  .  . 

17.00% 

Sundries  (4,  5,  8, 

9,  10,  ii,  12)  .  . 

13-18% 

Evaporation.  .  .  . 

32-50%* 

Total  

75-31% 

72  STEAM   ECONOMY 

DIAGRAM  3.  —  Juice  vapor  is  used  as  follows:  from 
the  first  body,  7%  for  the  vacuum  pans;  from  the  sec- 
ond body,  7%  for  diffusion,  10%  for  heaters  and  7%  for 
saturation. 

Boiler  and  Exhaust  Steam  g!         .       3 

Consumption:  C    .  o 

a   .2  s  £ 

Saturation  §      3  £  2 

(12.63-7) 5-63%       8     ISg| 

Vacuum  pans  ^    "W* 

(i7-7) 10.00% 

Sundries 13.18% 

Evaporation 4i.25%*~>I~~L_>II— L_»III  — Ljy— l_^io."25% 

Total 70.06% 

41.25  34.25     10.25     10.25 

Water  evaporation,  96%. 

DIAGRAM  4. —  The  preceding  distribution  of  vapors, 
but  with  a  juice  boiler  which  consumes  8%  of  direct 
steam. 


**      c 

Boiler  and  Exhaust  Steam  G       §  50 ! 

Consumption: 

Saturation ...  5 . 63  % 
Vacuum  pans .  i  o .  00% 
Sundries 13 . 18%  |  t  t  t 


„  .. 

Evaporation. 

Total  ........     68.06% 


8     39.25  32.25      8.25     8.25 


Water  evaporation,  96%. 
*  See  note  under  diagram  i. 


DISTRIBUTION   OF    STEAM    IN    THE    FACTORY       73 

DIAGRAM  5.  —  With  properly  operating  engines  and 
high  vapor  pressure  it  is  possible  with  the  preceding 
distribution  of  steam  to  use  the  juice  boiler  to  still  better 
advantage,  for  example: 

§ 


a 

O   w  +3 

Boiler  and  Exhaust  Steam 
Consumption: 

Saturation.  .  .       5  .63% 

I 

> 

1I| 

tjj    CT3  ,£j 

Vacuum  pans  .     i  o  .  00% 
Sundries  13.18% 

T 

^°?l 

(16.00%*  >O 
Evaporation. 

rft 

30.25      6.25    6.25 

(  21  .25/0 

Total  66.06% 

37-25 

16 

Water  evaporation,  96%. 

DIAGRAM  6.  —  The  preceding  distribution  of  vapors, 
but  with  3%  from  the  fourth  body  for  heaters. 


c   -.2 

Boiler  and  Exhaust  Steam                      S     -2  £  -£ 
Consumption:                                   3      3  «  S 
o     *S  rt  £ 
Saturation.  .  .       5  .  63%                ^    S  ffi  w 

Heaters. 

Vacuum  pans. 
Sundries  

IO.OO%                     &£     £££x£x 

13.18%           1    1  ^ 

CO 

T 

Evaporation  . 
Total  

(  16  .  oo%*  ->O  ~1_^I  —l_^II  —  u^III  - 

1  TA      **  r*O7                                 ^ 

i_»IV- 

7.75 

64-56% 
16   35-75  28.75     7-75 

^4.75% 


Water  evaporation,  96%. 
*  See  note  under  diagram  i. 


74  STEAM  ECONOMY 

DIAGRAM  7.  —  From  the  second  body  of  an  ordinary 
quadruple  effect,  juice  vapor  is  taken  for  diffusion  and 
heaters;  also  7%  for  saturation  and  16%  for  vacuum 
pans.  This  combination  will  be  possible  only  when  the 
sugar  industry  has  at  its  disposal  appropriate  vacuum 
pans  permitting  at  the  same  time  the  carrying  on  of  the 
rest  of  the  work  with  the  poorest  engine  arrangement. 

§ 

Boiler  and  Exhaust  Steam  ,_;  5 


^/VJllSUlli-ptJ 

Saturation.  .  . 

xrii* 

5-63% 

§.  g 

•a  §11 

Vacuum  pans 

te  as  3  w 
3&&$ 

(17-16)... 

1.00% 

£0^£^ 

t^.  O   t^-O 

Sundries  

13-18% 

tftf 

Evaporation  . 

44-00%*  _>! 

:~i  >II~~L 

Total  

63.81% 

44  44 


Water  evaporation,  96%. 

DIAGRAM  8. — The  same  distribution  of  vapors  as  in  dia- 
gram 7,  but  with  a  juice  boiler  which  receives  10%  vapors. 

w 

gjf 

Boiler  and  Exhaust  Steam  .2  ™  ±J  5 

Consumption: 

Saturation ...       5 . 63% 
Vacuum  pans .       i .  00% 

*"   M     ^^  ° 

Sundries 13.18%  t  T  T  T  5 

.10.00%= 

Evaporation. 


Total 61.31% 

10     41.5        41.5 


Water  evaporation,  96%. 

This  diagram  demonstrates  that  with  a  juice  boiler 
with  abundant  utilization  of  vapors  the  work  of  the  last 

*  See  note  under  diagram  i. 


DISTRIBUTION    OF    STEAM    IN    THE    FACTORY       75 

two  bodies  is  not  to  be  considered  at  all.     Therefrom 
arises  the  idea  of  omitting  them  altogether. 

DIAGRAM  9.  —  The  same  as  the  preceding  example, 
but  without  the  third  and  fourth  bodies;  the  second 
body  having  such  a  low  vacuum  that  the  heating  of  the 
total  number  of  stations  is  possible. 


Boiler  and  Exhaust  Steam 

«  .§§• 

O    W3  "  Tj    £ 

Consumption: 

1&1*1 

Saturation.  .  . 

5-63% 

Hi 

Vacuum  pans. 

1.00% 

Sundries  

13.18% 

l»0  C^g 

T  T  T  T 

Evaporation  . 

(I2.00%*->O-1_J- 
(»0    OQ0/                   12  t 

iJLilt  >2%  tO 

\  ^u  .  uu  /Q 

Total  

61.81% 

12 

+      42      +      42 

Water  evaporation,  96%. 

DIAGRAM  10.  —  The  same  as  the  preceding  example, 
but  with  the  taking  of  4%  from  the  first  body  for  the 
further  heating  of  the  saturation. 


Boiler  and  Exhaust  Steam 


Consumptic 

)n: 

s 

| 

w 

o 

a 
g 

Saturation 

pa 

u 

53 
d 

1 

ri 

i-< 

^ 

(5-63-4).. 

I 

.63% 

1 

S 

HP 

rt 

•> 

Vacuum  pans. 

I 

.00% 

s 

m 

H-i 

^ 

C/i 

^ 

^-i- 

^^ 

o 

t^ 

& 

Sundries  

13 

.18% 

T 

T 

1—  1 

T 

T 

M 

T 

Evaporation  . 

12 

.oo%*^0 

i?t 

-i  

—  -> 

ii- 

.  \J\J  /Q 

to  condenser. 


Total 59.81% 


12        +       44+4° 


Water  evaporation,  96%. 
*  See  note  under  diagram  i . 


76  STEAM  ECONOMY 

DIAGRAM  1 1 .  —  With  well-designed  and  properly  oper- 
ating engines  and  a  high  steam  pressure,  according  to 
the  preceding  example,  the  juice  boiler  ("  O  "  body)  can 
be  taxed  harder,  as  the  exhaust  steam  under  favorable 
conditions  can  drop  down  to  20%;  but  inasmuch  as, 
in  this  case,  the  total  quantity  of  vapors  developed  in 
the  second  body  might  not  suffice  for  all  purposes, 
then  of  the  16%  (which,  according  to  diagram  10,  the 
second  body  should  furnish  for  the  vacuum  pans),  10% 
is  carried  over  to  the  first  body  which  further  facili- 
tates the  practicability  of  such  arrangement. 

c/3  in 

B  O 

<-*  rH      ^ 

Boiler  and  Exhaust  Steam  '•£  g    .§  2T**  S 

Consumption:  £j  p     w  o>  &  3 

Saturation...       1.63% 

Vacuum  pans .       i .  00% 

*$•  o    t*~  o  ^»H-> 

Sundries 13.18%  j|     TTTT 

>%  to  condenser. 

.22.00%-  "f 


Evaporation.   [™°  ^°~^\ 
Total 59.81% 


22     +     44  -f  30 
Water  evaporation,  96%. 

If  the  practicability  of  a  system  utilizing  the  vapors 
for  the  purpose  of  heating  the  vacuum  pans  from  the 
second  body  is  indeed  a  question  of  moment,  then  the 
following  example  is  in  accordance  with  the  present  prac- 
tice. There  arose  in  a  factory  producing  from  25  to  30% 
exhaust  steam,  equipped  with  a  triple  effect,  the  prob- 

*  See  note  under  diagram  i. 


DISTRIBUTION    OF   STEAM    IN    THE    FACTORY       77 

lem  of  obtaining  good  results  by  the  most  simple  means. 
The  author  designed  the  installation  according  to 
diagram  12,  where  the  conditions  are  not  altogether 
similar  to  those  given  in  diagrams  i  to  n. 

DIAGRAM  12.  —  Draw  of  juice  110%.  Thickening  of 
the  juice  to  the  highest  degree  in  the  evaporation,  as 
near  as  possible  to  70°  Brix:  i.e.,  that  portion  of  the 
thick  juice,  which  in  the  vacuum  pans  reaches  to 
the  level  of  the  proof  stick.  The  filter  presses  not 
steamed.  Exclusive  heating  of  the  vacuum  pans  from 
the  juice  boiler;  besides  also  i%  for  taking  care  of  the 
centrifugals.  From  the  first  body  4%,  for  the  third 
saturation,  and  1.6%  for  the^heating  of  the  thick  juice 
and  syrup.  From  the  second  body,  heating  of  the  dif- 
fusion, the  raw  juice  heaters  and  about  8%  for  the  first 
and  second  saturations. 


Boiler  and  Exhaust  Steam 
Consumption: 

Items  5,  ii  and  12 

from  Table  13 

Direct  steam  in  the 

juice  boiler 

Exhaust  steam 

Total 59-71% 

24  33.8     28.2 


Water  evaporation,  90%. 


78  STEAM  ECONOMY 

The  diagrams  show  that,  with  a  juice  boiler  and 
sufficient  utilization  of  the  heating  vapors  from  the  juice, 
a  quadruple  effect  does  not  by  any  means  give  better 
results  than  a  double  or  triple  effect  system. 

The  difference  lies  in  the  fact  that,  with  a  double- 
effect  system,  one  would  be  compelled  to  complete  the 
thickening  of  the  juice  at  about  203°;  which  fact,  with 
the  customary  construction  of  the  evaporating  appara- 
tus, would  involve  somewhat  larger  sugar  losses.  These, 
however,  could  be  very  much  reduced  by  the  greatest 
possible  reduction  of  the  juice  spaces. 

The  reduction  of  the  spaces  taken  up  by  the  juice, 
by  one-half,  or  one-third,  contrary  to  common  practice, 
does  not  appear  to  be  especially  difficult  with  vertical 
evaporating  bodies. 

Too  often,  indeed,  there  is  seen  in  practice  altogether 
absurd  efforts,  and  many  a  leading  firm  turns  the  heads 
of  the  people  with  so-called  improved  vertical  evapora- 
ting bodies  with  juice  circulation  through  the  center  and 
around  the  heating  chambers;  as  also  with  horizontal 
bodies,  with  heating  elements,  which  are  composed  of 
chambers  containing  bundles  of  expanded  tubes  set 
crosswise  to  each  other.  The  one,  as  also  the  other, 
constitutes  an  altogether  foolish  retrogression,  as  such 
arrangements,  without  even  giving  anything  positive, 
greatly  increase  the  juice  content. 

Naturally,  the  considerations  concerning  the  adoption 
of  a  double-effect  system  with  a  very  low  vacuum  in 
the  last  body  is,  at  present,  a  vision  of  the  future;  but 
since  there  is  set  before  us  the  problem  of  making 


DISTRIBUTION    OF    STEAM   IN    THE    FACTORY       79 

plain  the  theory  of  steam  economy  in  the  sugar 
factory,  to  show  the  way  by  which  one  can  progress 
towards  securing  still  better  results  is  not  to  be 
ignored. 

That,  for  this  reason,  one  must  not  expect,  by  any 
means,  to  limit  himself  to  the  vertical  evaporating 
bodies  is  self-evident. 

Perhaps  it  may  be  recommendable  to  once  more  revise 
the  principle  of  film  evaporation,  which,  if  properly  used, 
would  give  good  results.  Until  the  present  day  it  has 
not  been  seen  what  advantages  this  could  offer  over  the 
old  system  since  no  more  is  secured  from  the  increased 
transference  of  heat  through  an  induced  circulation. 

These  advantages  can  be  realized  whenever  it  is  a 
question  of  reducing  the  period  of  evaporation  to  a 
minimum  and  to  diminish  the  useless  losses  of  drop  in 
temperature. 

It  should  not  be  forgotten  that  the  diagrams  for  the 
utilization  of  vapors  conform  with  an  altogether  deter- 
mined method  of  operation,  under  average  conditions. 

The  use  of  dry  lime  instead  of  milk  of  lime  would 
reduce  it  about  2.5  to  3.5%.  Diminished  draw  of 
juice  for  the  diffusion,  less  lime,  the  elaborating  of  raw 
sugar,  etc.,  would  further  economize  10%  vapor  and 
more.  Concerning  these,  some  data  are  given  in  the 
following  chapter. 


80  STEAM   ECONOMY 

THE  INFLUENCE  OF  THE  METHODS  OF  OPERA- 
TION OF  THE  SEVERAL  STATIONS  ON  THE 
TOTAL  STEAM  CONSUMPTION. 

Having  laid  down  in  previous  pages  the  leading  prin- 
ciples, which  are  of  importance  for  the  proper  manage- 
ment of  steam  in  a  sugar  factory,  we  can  consider 
our  object  as  accomplished;  but,  for  the  sake  of  com- 
pleteness, we  will  discuss  a  few  more  questions  which 
frequently  come  to  the  mind  of  a  technical  sugar  man, 
from  the  standpoint  of  steam  consumption. 

(i)  What  is  the  loss  occasioned  by  a  small  diffusion 
through  excessive  draw  of  juice;  what  economy  would 
a  large  diffusion  effect? 

In  order  to  answer  such  a  question,  it  is  necessary 
to  go  from  the  diffusion  through  all  of  the  suc- 
ceeding stations.  Let  us  do  this  and  see  afterwards  at 
which  points  and  to  what  extent  each  10%  increase 
of  juice  draft  (for  the  diffusion)  will  affect  the  steam 
consumption. 

Diffusion.  --  Table  i  shows  that  the  steam  con- 
sumption for  the  diffusion  not  only  does  not  fall  with  the 
diminution  of  the  draw,  but  on  the  contrary  under  usual 
conditions  of  operation  (where  the  temperature  of  the 
diffusion  water  is  higher  than  the  temperature  of  the 
juice)  even  rises  somewhat. 

Moreover,  the  losses  through  radiation  in  a  larger 
diffusion  are  inevitably  larger. 

At  this  station  the  steam  consumption  also  increases 
somewhat  with  the  enlarging  of  the  battery. 


DISTRIBUTION    OF    STEAM    IN    THE    FACTORY       8 1 

Raw  Juice  Heater.  -  -  Table  2  indicates  that  the 
diminution  of  the  juice  draw  by  10%,  with  the  cus- 
tomary heating  through  90°,  reduces  the  demand  for 
heat  by  about  0.8%. 

Saturation.  —  One  can  easily  see  that  all  the  items 
which  have  been  placed  together  in  their  proper  places 
(pages  17  to  20)  under  the  headings  (B),  (C),  (D),  (E)  and 
(F)  do  not  depend  in  any  way  upon  the  draw;  this  last 
will  have  influence  only  on  item  (A).  For  the  satura- 
tions, the  average  temperature  difference  between  the 
juice  which  enters  into  the  first  saturation  and  that  which 
goes  into  the  first  evaporating  body  is  about  18°.  Every 
additional  10%  of  water  occasions,  therefore,  an  in- 
creased expenditure  of  steam  in  the  ratio  of —  = 

970 

0.185%. 

Evaporation.  —  For  a  quadruple  evaporation,  each 
additional  10%  water  occasions  an  increased  use  of 

—  =    2.5%  steam;    correspondingly  more  with  a  less 
4 
number  of  bodies. 

ALL  OTHER  STATIONS  occasion  no  increased  expendi- 
ture, provided  the  evaporating  station  is  large  enough  to 
deliver  at  all  times  a  juice  sufficiently  thick. 

If  we  add  together  all  the  items  specified,  we  find  that, 
with  a  quadruple  effect  and  with  the  use  of  boiler  and 
exhaust  steam  for  heating  and  saturation,  for  every  10% 
increase  in  draw  a  total  of  3.5%  increase  in  steam  will 
be  expended. 

If  the  heaters  be  heated  from  the  second  body,  the 


82  STEAM   ECONOMY 

increased  expenditure  here  falls  off  by  50%,  that  is,  from 
0.8  to  0.4%  and  the  total  utilization  from  3.5  to  3.1%. 

Naturally,  in  carrying  on  the  diffusion,  sight  must  not 
be  lost  of  the  biological  sugar  losses,  since  these  grow  in 
exact  proportion  to  its  duration. 

(2)  How  does  the  use  of  a  lime  kiln,  instead  of  taking 
the  saturation  gas  from  the  smoke  flue  of  a  wood-fired 
installation,  influence  the  steam  consumption? 

This  influence  is  to  be  seen  directly  from  Table  8,  as 
it  gives  clear  data  relative  to  the  steam  consumption 
for  varying  qualities  of  gas  and  additions  of  lime,  if  the 
average  temperature  of  the  escaping  gases  be  176°. 

For  example,  the  change  from  15%  gas  to  28%  gas, 
with  3%  lime,  gives  an  economy  of  19.11—11.76  =  7.35%. 

For  other  temperatures  a  correction  must  be  made 
according  to  Table  6.  For  example,  this  table  gives  for 
each  i%  lime  between  176°  and  167°,  with  15%  C02  a 
difference  of  3.87  —  2.73  =  1.14%;  with  28%  CO2,  1.42 
—  i. oo  =  0.42%.  With  3%  lime  the  difference  between 
176°  and  167°  would  amount  to  (1.14  —  0.42)  3  =  2.16%. 

At  167°  the  economy  would  be  equal  to  7.45  —  2.16  = 

S-29%. 

(3)  How  will  the  steam  consumption  be  affected  by 
the  addition  of  i%  of  lime? 

The  result  of  adding  one  more  part  of  lime  to  every  100 
parts  of  beets  makes  itself  felt  in  an  increase  of  steam  con- 
sumption in  the  saturation  itself,  as  also  in  the  necessity 
for  evaporating  more  water  in  the  evaporation  system. 

Saturation.  —  This  question  is  answered  in  Table  6, 
which  indicates,  for  instance,  that  at  176°,  according  to 


DISTRIBUTION   OF    STEAM    IN   THE    FACTORY       83 

the  quality  of  the  gas,  this  steam  consumption  for  i% 
of  lime  with  30%  carbon  dioxide  gas  amounts  to  1.28%; 
with  25%  gas,  to  1.71%;  with  20%,  to  2.42%;  and  with 
i5%,  to  3.87%. 

Evaporation.  —  With  each  i%  of  lime  there  will  be 
introduced  4%  more  water  which  will  consume,  for  its 
evaporation  in  a  quadruple  system,  i%  of  steam.  In 
total,  therefore,  at  176°  and  with  30%  CO2,  each  i%  of 
lime  increases  the  steam  consumption  by  2.28%;  with 
25%  gas,  by  2.71%;  with  20%  gas,  by  3.42%;  and 
with  1 5%  gas,  by  4.87%. 

(4)  How  does  the  steam  consumption  change  with  each 
9°  difference  in  the  average  temperature  of  the  saturation 
juice  ? 

This  question  is  answered  in  Table  6,  by  multiplying  the 
difference  between  the  two  values  set  under  one  another 
by  the  percentage  of  lime,  and  reducing  the  product,  for 
a  quadruple  effect,  by  25%,  because  the  evaporation  of 
each  4%  water  in  the  saturations  diminishes  the  steam 
consumption  by  an  evaporation  equal  to  i%. 

For  a  triple  evaporation  the  product  must  not  be 
reduced  by  25%  but  by  33.3%. 

In  this  manner,  with  25%  of  gas  and  3%  of  lime,  the 
change  in  the  temperature  of  the  saturation  gas  from 
185  to  176°  in  a  quadruple  system  saves 

(2.56-1.71)3X^=1.91%; 
with  a  change  from  176  to  167°, 

(1.71  -  1.20)3  X-15-  =  1.15%. 
100 


84  STEAM  ECONOMY 

Were  the  saturations  heated  with  juice  vapors,  the 
economy  would  also  diminish  correspondingly. 

(5)  How  much  more  total  steam  would  be  expended 
for  the  saturations  by  the  use  of  perforated  coils,  in  lieu 
of  serpentine  coils  or  steam  heating  drums? 

The  consumption  of  steam  for  the  saturation  itself  re- 
mains practically  unchanged  whether  the  heat  is  secured 
through  open  coils  or  through  serpentines;  but,  with  the 
open  coils,  the  whole  of  the  condensed  water  goes  into 
the  juice  and  must  then  be  re-evaporated  with  an  ex- 
penditure, in  a  quadruple  effect,  of  one-fourth  of  the 
total  quantity  of  steam  used  in  the  saturation,  and  in  a 
triple  effect  of  one- third.  In  the  saturation  carried  on 
with  open  coils  the  utilization  of  14%  of  steam  occasions 

an  increased  consumption  of  --  =  3.5%  in  a  quadruple 

4 

effect  and  —  =  4.67%  in  a  triple  effect. 

o 

Naturally,  this  greater  consumption  can  be  corre- 
spondingly increased  if  more  moist  steam  is  used  and 
there  enters  into  the  juice  with  it  much  previously  con- 
densed water.  If,  therefore,  conditions  compel  the  use  of 
open  steam  coils,  care  should  be  taken  that  the  steam  be 
drawn  from  the  driest  point  of  the  pipes  (not  towards 
the  end  of  a  steam  header)  or,  what  is  still  better,  that 
it  be  previously  passed  through  a  steam  separator. 

(6)  How  much  higher  is  the  total  steam  consumption 
with  the  use  of  open  steam  coils  for  the  heating  of  the 
thick  juice  and  the  syrup? 

If  the  vacuum  pans  are  heated  exclusively  with  boiler 


DISTRIBUTION   OF    STEAM    IN    THE    FACTORY       85 

(direct)  steam,  it  will  be  necessary  to  re-evaporate  here 
the  surplus  water  introduced  with  an  expenditure  of 
1.1%  steam  for  every  i%  of  water.  The  heating  with 
open  steam  coils  proves  to  be  here  a  very  expensive 
method.  By  the  utilization  of  juice  vapors  for  boiling, 
this  increased  expenditure  is  correspondingly  diminished. 

(7)  How  much  higher  is  the  steam  consumption  with 
the  use  of  open  coils  for  heating  of  the  wash  syrup 
and  the  green  syrup  which  are  returned  into  the  first 
product  ? 

The  answer  to  this  question  is  given  in  the  solution 
of  questions  (5)  and  (6) ,  according  as  these  products  are 
introduced  either  in  the  thin  juice  previous  to  the  evapo- 
rating station,  or  in  the  thick  juice  after  that  station. 

(8)  How  does  the  consumption  of  the  steam  vary 
if,  instead  of  thick  juice  of  60°  Brix,  juice  of  50°  Brix  or 
40°  Brix  be  introduced  for  boiling? 

In  accordance  with  Example  6,  page  31,  we  would 
get  under  the  average  conditions  of  work  37.85%  of 
thick  juice  of  60°  Brix. 

Were  it  pumped  out  of  the  evaporators  as  thick  juice 
of  50°  Brix,  there  would  be  a  greater  volume  of  it,  namely : 

37.85X^  =  4542%. 

0 

The  vacuum  pans   would,  therefore,  have   45.42  - 
37.85  =  7.57%  more  water  to  evaporate,  which  would 
amount  to  an  expenditure   of   steam   of   7.57  X  i.i  = 

8-33%- 

On  the  other  hand,  the  evaporating  station  being  of 
the  quadruple  system  for  7.57%  of  water  would  con- 


86  STEAM  ECONOMY 

sume  7.57  X  -^  =  1.89%  less  steam,  so  the  total  steam 
100 

consumption  is  only  8.33  —  1.89  =  6.44%  higher. 
40°  Brix  would  make  the  total  quantity  of  thick  juice 

37.85  X  —  =  56.77%,  and  the  vacuum  pans  would  have 
40 

56.77  —  37-85  =  18.92%  more  water  to  evaporate  and 
that  with  an  increase  of  18.92  X  i.io  =  20.81%  steam. 

1  £ 

But  as  the  evaporating  station  consumes  18.92  X  — ^  = 

100 

4-73%  IGSS>  the  total  expenditure  is  20.81—4.73  =  16.08%. 
Were  the  vacuum  pans  heated  exclusively  from  the 
second  body,  the  increased  expenditure  would  amount 
to  only  one-half. 

CALCULATION  OF  THE  HEATING  SURFACES. 

After  having  decided  upon  the  proper  diagram  to  be 
selected  for  the  distribution  of  the  steam  —  according  to 
the  existing  local  conditions  —  the  calculation  for  the 
heating  surfaces  of  the  evaporators  and  for  all  the  heat- 
ing stations  can  be  considered.  In  order  to  do  so, 
the'  known  coefficients  of  heat  transmission  (obtained 
by  experiment  or  through  experience)  and  the  drop  in 
heat  of  each  individual  apparatus  are  used,  taking 
care,  on  the  one  hand,  that  the  regular  function  of  each 
is  not  interfered  with,  and  avoiding,  on  the  other,  the 
possibility  of  sacrificing  other  stations  considered  in  the 
heating  combinations. 

It  is  not  necessary  to  mention  especially  that  all  these 
factors  can  have  no  direct  influence  upon  the  steam  con- 


DISTRIBUTION    OF    STEAM    IN    THE    FACTORY       87 

sumption,  because  all  deductions  are  entirely  independ- 
ent of  the  size  of  the  heating  surfaces,  their  relations 
to  each  other,  the  materials  of  which  they  are  made 
or,  finally,  whether  or  not  they  are  covered  with  scale. 

Differences  in  the  size  of  the  heating  surfaces  or  in 
their  material  and  their  condition  can  only  bring  about 
other  transmission  coefficients,  or  rather,  the  possibility 
or  impossibility  of  obtaining  the  desired  result  or  the 
desired  productivity  from  a  given  heating  surface. 
Thus,  if  the  desired  evaporation  or  heating  is  secured, 
then  the  steam  consumption  is  entirely  independent  of 
all  these  circumstances. 

It  is  the  task  of  the  engineer  to  proportion  all  the 
stations  in  such  a  way  that  with  the  elaboration  desired, 
the  required  temperatures  will  set  in  everywhere-  of 
themselves,  so  that  with  given  temperatures  the  neces- 
sary heat  transference  will  result.  In  order  to  obtain 
this,  only  the  most  simple  calculations  with  the  known 
heat-transference  coefficients  (easily  determined  in  prac- 
tice) have  to  be  made,  according  to  the  equation : 

Heating  surface  = 

number  of  heat  units  to  be  transferred 
temperature  difference  X  transmission  coefficients 

in  which  equation,  as  a  matter  of  course,  the  number  of 
the  heat  units  to  be  transferred  and  the  transmission 
coefficient  have  to  be  brought  into  relation  with  .one 
and  the  same  time-unit,  usually  a  minute.  Under  the 
heading  "  temperature  difference,"  the  useful  drop  of 
heat  is  to  be  understood.  For  the  facilitation  of  such 


88 


STEAM  ECONOMY 


calculations  and  also  for  other  purposes,  such  as  the 
determination  of  the  pipe  diameter  for  steam,  water  and 
juice  lines,  Table  1 5  can  be  used  to  advantage,  as  it  gives 
the  amount  of  beets  which  is  to  be  worked  up  per  hour, 
minute  and  second  for  every  daily  elaboration. 


TABLE   15. 

Giving  the  Slicings  per  Hour,  per  Minute  and  per  Second,  Corre- 
sponding to  Daily  Capacities  from  300  to  3000  Tons. 


Tons  per  day. 

Tons  per  hour. 

Pounds  per  minute. 

Pounds  per  second. 

300 

12.50 

416.6 

6.94 

400 

16.66 

555-5 

9.26 

500 

20.83 

694.4 

n-57 

600 

25.00 

833-3 

13-88 

700 

29.  16 

972.1 

16.20 

800 

33-33 

mi  .0 

18.51 

QOO 

37-50 

1249.9 

20.83 

1000 

41.66 

1388.8 

23-15 

IIOO 

45-83 

1527-7 

25.46 

I20O 

50.00 

1666.6 

27.77 

1300 

54-17 

1805.4 

30.09 

I4OO 

58.33 

IQ44-3 

32.40 

1500 

62.50 

2083  .  i 

34.71 

1600 

66.66 

2222.0 

37-03 

1700 

70.83 

2360.8 

39-35 

I800 

75.00 

2499  .  7 

41  .66 

I90O 

79.17 

2638.6 

43-98 

2000 

83-32 

2777-5 

46.29 

2IOO 

87-50 

2916.4 

48.31 

22OO 

91  .66 

3055.3 

50.92 

2300 

95-83 

3194.2 

53-24 

24OO 

IOO.OO 

3333-1 

55-55 

2500 

104.17 

3472.0 

-    57-86 

26OO 

108.33 

3610.8 

60.  18 

27OO 

112.50 

3749-7 

62.49 

2800 

116.67 

3888.6 

64.81 

29OO 

120.83 

4027.4 

67.12 

3000 

125.00 

4166.3 

69.44 

DISTRIBUTION    OF    STEAM    IN    THE    FACTORY       89 

By  means  of  this  table  it  is  easy  to  determine  the 
quantity  of  juice  which  is  passing  this  or  that  station, 
the  quantity  of  water  evaporated  in  this  or  that  body, 
the  quantity  of  steam  received  through  this  or  that  line, 
and  so  on.* 

EXAMPLE  18. — According  to  Example  10,  page  36,  15.04% 
water  is  evaporated  in  the  vacuum  pan.  How  many  pounds  are 
evaporated  per  minute  for  a  daily  slicing  of  440  tons  of  beets  ? 

According  to  Table  15,  for  this  capacity  there  are  609  pounds 

of  beets  per  minute,  thus  609  X  I5'°4  =  91.6  pounds  of  water 

100 

are  evaporated  in  the  vacuum  pan  per  minute. 

EXAMPLE  19.  —  How  large  must  be  the  heating  surfaces  of 
bodies  I,  II,  III  and  IV  if,  with  a  daily  slicing  of  660  tons  of  beets, 
the  steam  distribution  is  to  be  installed  according  to  diagram  7, 
page  74,  assuming  a  useful  temperature  drop  of  9°,  10.8°,  14.4° 
and  27°,f  and  a  heat  transference  of  10.24,  7.17,  4.1  and  2.05 
B.t.u.'s  per  square  foot  for  each  degree  difference  in  temperature? 

*  The  figures  for  the  hourly  slicings  are  well  suited  for  the  deter- 
mination of  the  diameter  of  the  steam  pipes.  It  is  only  necessary  to 
multiply  the  particular  number  in  the  table  by  the  percentage  of  steam 
passing  through  the  pipe,  according  to  diagram,  and  to  look  for  the 
nearest  number  in  the  corresponding  column  in  Hausbrand's  Table  32. 
The  number  of  "  pounds  per  minute  "  is  well  suited  for  the  calculation 
of  heating  surfaces,  and  the  number  of  "pounds  per  second"  well 
adapted  for  the  calculation  of  the  water  and  juice  pipes. 

f  With  a  total  heat  drop  of  36°,  page  61,  this  corresponds  to  a 
temperature  difference  of  97.2°  between  exhaust  steam  and  vapors  from 
the  last  body.  Thus,  if  the  expected  vacuum  is  24.6  inches  of  mercury, 
corresponding  to  136.4°,  the  exhaust  steam  must  have  a  temperature 
of  136.4  +  97.2  =  233.6°,  equal  to  a  pressure  of  8.1  pounds  per  square 
inch. 


9° 


STEAM   ECONOMY 


HAUSBRAND'S  TABLE.     (No.  32.) 

Total  Weight  of  Steam  in  pounds,  which  passes  in  one  hour  through  pipes 

from  i  to  36  inches  in  diameter  and  80  feet  long,  at  pressures  between 

88.2  and  1.058  pounds  per  square  inch  absolute  with 

0.5%  loss  of  pressure. 


Absolute    pres- 

sure, Ibs.  per 

sq.  in  

88.2 

73-5 

58.8 

44.1 

29.4 

22 

14-7 

12.24 

10.96 

Absolute    pres- 

sure,     inches 

mercury  

1  80 

150 

I2O 

90 

60 

45 

30 

25 

22.4 

Vacuum,  inches 

mercury 

c 

7  6 

Diameter 
of  pipe, 
inches. 

Velocity 
of  steam  , 
feet  per 
second. 

The  weight  of  steam  in  pounds  which  passes  through  the  pipe  in  one  hour 
with  0.5%  loss  of  pressure. 

1.0 

27.9 

no 

92 

75 

57 

40 

I  .2 

29-5 

i6s 

138 

112 

86 

59 

i-4 

31.2 

236 

198 

1  60 

121 

84 

1.6 

34-4 

34i 

286 

233 

I78 

121 

92 

2.0 

37-7 

582 

492 

398 

3°4 

209 

158 

108 

2.4 

42.7 

950 

800 

647 

493 

336 

259 

176 

3-15 

47.6 

i,  880 

1,582 

I,5°4 

980 

672 

510 

350 

292 

264 

3-54 

49.2 

2,460 

2,075 

1,682 

1,282 

872 

670 

458 

385 

343 

3-97 

50.8 

3.140 

2,650 

2,148 

1,640 

1,120 

855 

605 

493 

440 

4.72 

55-8 

5.650 

4,770 

3.870 

2,952 

2,O4O 

1,540 

1,054 

886 

800 

5-9° 

60.7 

8,390 

7,080 

5.740 

4,370 

2,990 

2,282 

1,560 

1,316 

1,182 

6.90 

65-6 

12,470 

10,460 

8,470 

6,450 

4,440 

3.375 

2.3J5 

1.952 

i,752 

7.88 

7°-5 

14,520 

1  1,  800 

8,990 

6,220 

4,740 

3.240 

2,735 

2,460 

8.86 

75-5 

l6,220 

12,380 

8,380 

6,400 

4,480 

3,690 

3.320 

o  8s 

78  8 

IO,8OO 

8,260 

5,520 

4,760 

4,280 

ii  80 

87  o 

13,200 

8,980 

7.58o 

6,820 

1-271; 

CH  'i 

19,260 

13,150 

i  i,  080 

9,990 

T  r    7r 

IOO    O 

18,380 

i  5  ,  500 

13,920 

17    7O 

106  8 

20,900 

18,800 

IO    7O 

in  ^ 

27,000 

24,280 

21    6? 

1  16  4 

31,800 

2  -2    60 

T  22    O 

25    60 

1  26    2 

27    S^ 

I  3O    3 

iO^-6 
I  36    O 

35-40 

151  .0 

DISTRIBUTION   OF    STEAM    IN    THE    FACTORY        91 


HAUSBRAND'S  TABLE.     (Continued.) 

Total  Weight  of  Steam  in  pounds,  which  passes  in  one  hour  through  pipes 

from  i  to  36  inches  in  diameter  and  80  feet  long,  at  pressures  between 

88.2  and  1.058  pounds  per  square  inch  absolute  with 

0.5%  loss  of  pressure. 


Absolute    pres- 

sure, Ibs.  per 

so  .    in.  . 

IO.28 

7    5r 

C     C2 

3          78 

2    87 

2.28 

i  ?6 

i  ot;8 

Absolute    pres- 

/  oo 

O    O 

O  '  /  ^ 

"  *W| 

*  •  /** 

J.    .  V-*^*-* 

sure,      inches 

mercury  

21  .O 

15-0 

11.23 

7.72 

5.86 

4-65 

3-60 

2.16 

Vacuum,  inches 

mercury  

Q.O 

15-0 

18.77 

22.28 

24.14 

25-35 

26.40 

27.84 

Diameter 
of  pipe, 

Velocity 
of  steam  , 
feet  per 

The  weight  of  steam  in  pounds  which  passes  through  the  pipe  in  one  hour 
with  0.5%  loss  of  pressure. 

second. 

I  .0 

27.9 

1.2 

29-5 

1.4 

31.2 

1.6 

34-4 

2.O 

37-7 

2.4 

42.7 

\ 

3-15 

47.6 

3-54 

49.2 

324 

240 

185 

3-97 

50.8 

414 

308 

236 

158 

125 

IOI 

81.5 

49-5. 

4.72 

55-8 

742 

555 

416 

293 

226 

182 

145 

no 
00 

5-QO 

60.7 

1,103 

823 

627 

433 

349 

271 

216 

132 

6.90 

65.6 

1,627 

1,219 

928 

645 

497 

403 

317 

196 

7.88 

70-5 

2,290 

1,708 

1,308 

9°4 

700 

562 

445 

273 

8.86 

75-5 

3,095 

2,320 

1,762 

1,220 

948 

760 

603 

354 

9-85 

78.8 

3.998 

2,990 

2,278 

1,573 

1,413 

1,220 

777 

476 

11.80 

87.0 

6,360 

4,740 

3,620 

2,510 

i,95o 

1,558 

1,217 

759 

13-75 

93-5 

9.3io 

6,940 

5,300 

3,670 

2,845 

2,285 

1,810 

I,  IIO 

iS-75 

IOO.O 

13,000 

9,700 

7,420 

'5,i7o 

3,721 

3,190 

2,362 

i»552 

17.70 

106.8 

17.500 

13,030 

10,000 

6,920 

5.36o 

4,300 

3,410 

2,090 

19.70 

in.  5 

22,620 

16,880 

12,900 

8,930 

6,930 

5,560 

4,400 

2,695 

21.65 

116.4 

28,500 

21,280 

16,290 

11,300 

8,740 

7,O2O 

5,570 

3,4io 

23.60 

123.0 



26,850 

20,500 

14,200 

11,000 

8,830 

7,000 

4,260 

2<.6o 

126.  2 

24.  A2O 

17,1  oo 

T  7     0  CO 

10  6"?o 

8,810 

ST  *7O 

**o  •  v 

27.55 

130.3 

^.L^y^^^J 
28,94O 

20,860 

*o>^5w 

18,180 

13,080 

10,300 

,-L/U 
6,320 

29.50 

136.0 

24,430 

21,370 

16,280 

12,900 

7,920 

35.40 

I5I.O 

30,400 

24,380 

19,300 

11,850 

92  STEAM   ECONOMY 

In  the  first  body,  44%  water  (see  diagram  7)  is 
evaporated;  besides,  there  is  used  2.66%  steam  for  the 
heating  of  the  entering  thin  juice  up  to  the  boiling  tem- 
perature in  the  body  (Example  4,  page  30),  thus,  in 
total,  44  +  2.66  =  46.66%. 

Thus,  with  a  daily  capacity  of  660  tons  (according  to 

Table  15),  915  X  ^— : —  =427  pounds  steam  per  minute, 
100 

which  is  equal  to  427  X  954  =  407,358  B.t.u.'s  per  min- 
ute.    Therefore,  in  our  case  there  is  =  4420 

9  X  10.24 

square  feet  (approximately)  heating  surface  necessary 
for  transference. 

In  the  second  body  there  is  also  44%  evaporated, 
which  corresponds,  for  a  capacity  of  660  tons,  to  915  X 

-™-  =  402.5  pounds  steam,  which  is  equal  to  402.5  X 

IOO 

954  =  383,985  B.t.u.'s  per  minute,  for  which       0 

10. 8X  7.17 

=  4960  (approximately)  square  feet  heating  surface  is 
required. 

In  the  third  body  there  is  4%  water  evaporated,  or 

915  X  — ^  =  36.6   pounds   per  minute,  equivalent    to 
100 

36.6  X  954  =  34,9i6  B.t.u.'s,for  which     34fT    -  =  592 

14.4  X  4-1 

square  feet  (approximately)  heating  surface  is  necessary 
for  transference. 

Finally,  in  the  fourth  body,  4%  is  evaporated,  or 
36.6  pounds  per  minute,  equivalent  to  34,916  B.t.u.'s,  for 


DISTRIBUTION   OF   STEAM    IN   THE   FACTORY       93 

which     -34'91 —  =  635  square  feet  (approximately)  of 
27  X  2.05 

heating  surface  is  necessary. 

It  is  hardly  necessary  to  mention  that  too  much  stress 
is  no.  to  be  laid  upon  these  figures.  In  the  given  case 
it  would,  perhaps,  be  better  for  the  machinery  builders 
i  they  can  make  bodies  I  and  II  of  the  same  size,  say 
of  about  4840  square  feet,  a  fact  which  would  cause  only 
small  deviation  from  the  normal  temperatures.  It  is 
also  recommended  to  make  the  last  two  bodies  alike, 
say  645  square  feet,  but  it  would  be  much  better  to  make 
tb  3m  somewhat  larger,  in  order  not  to  be  troubled  by 
the  gradual  formation  of  scale.  As  long  as  the  heating 
surfaces  are  clean,  it  will  not  be  difficult  to  obtain  the 
desired  temperatures  in  bodies  I  and  II,  by  closing  the 
ammonia  valves  in  bodies  III  and  IV. 

EXAMPLE  20.  — How  large  must  be  the  heater  if,  with  a  daily 
slicing  of  440  tons  of  beets,  the  raw  juice  is  to  be  heated  from  95 
to  185°,  using  the  vapors  from  the  second  body  with  a  temperature 
of  about  203°?  Let  the  draw  of  juice  be  120%,  the  heat  trans- 
ference be  4.5  B.t.u.'s  per  minute  per  square  foot  for  each  degree 
difference  in  temperature.  According  to  Table  15,  the  slicing  of 
beets  per  minute  is  610  pounds.  According  to  Table  2,  in  that 
case,  9720  B.t.u.'s  are  necessary  per  100  pounds  beets,  then  for 

610  pounds  =  —  X  9720  =  59,300  B.t.u.'s. 

IOO 

The  average  temperature  difference  is  calculated  from  Haus- 
brand's  tables  as  50.2°;  thus  the  heating  surface  must  be: 

$9>3°°    =  2622  square  feet. 
50.2X4-5 


94  STEAM  ECONOMY 

CLOSING  REMARKS. 

For  a  plant  which  is  being  operated  according  to  the 
methods  given,  there  results  a  steam  consumption  of 
about  75%  on  the  weight  of  the  beets,  which  will  drop 
to  70%  (according  to  diagram  3)  with  a  relatively 
complete  outfit,  by  the  heating  of  the  diffusion  and  the 
raw  juice  from  the  second  body  of  a  quadruple  evapora- 
tion (diagram  2). 

With  better  machinery,  fed  with  steam  of  a  higher 
tension,  it  is  possible  to  feed  an  "O"  body  or  a  " juice 
boiler"  with  8  to  16%  of  direct  steam  (diagrams  4  and 
5),  whereby  the  steam  consumption  drops  to  68  or  66% 
respectively.  If  the  vacuum  pans  are  heated  exclusively 
with  juice  vapors  and  the  utilization  of  the  latter  carried 
to  the  extreme,  it  may  be  possible  to  apply  the  Pauly 
process  still  further  and  to  get  a  steam  consumption  of 
60%  even  with  a  reduced  number  of  bodies.  With  the 
lowest  possible  draw  of  juice,  with  dry  lime,  and  when 
elaborating  raw  sugar,  the  consumption  can  still  be 
lowered  by  about  10%.  On  the  other  hand,  it  is  clear 
that  with  thick  juice  of  low  densities,  with  perforated 
coils  in  the  saturation,  with  an  incomplete  utilization 
of  exhaust  steam  and  similar  deficiencies  in  the  whole 
arrangement  and  methods  of  working,  the  steam  con- 
sumption can  be  100%  and  over.  By  reason  of  these 
figures,  it  is  not  difficult  to  realize  how  high  the  fuel 
consumption  may  be. 

In  all  the  calculations  it  is  assumed  that  the  con- 
densed waters  leave  the  heating  chambers  at  tempera- 


DISTRIBUTION    OF    STEAM    IN    THE    FACTORY       95 

tures  approaching  that  of  the  steam  in  them.  As,  for 
the  feeding  of  the  boilers,  only  part  of  this  water  is 
necessary,  it  is  by  no  means  difficult  to  select  that  por- 
tion which  is  not  under  212°,  for  this  purpose.  Under 
these  conditions,  there  may  be  expected  an  eightfold 
evaporation,  even  with  average  results  from  a  medium 
grade  of  coal.  Under  favorable  conditions  possible 
in  sugar  manufacture  (absence  of  scale  in  boilers,  the 
possibility  of  an  exact  control  of  operation,  the  use  of 
compound  boilers  which  permit  the  highest  efficiency), 
even  a  ninefold  evaporation  is  not  an  extremely  high 
result.  Therefore,  the  consumption  of  a  medium  grade 
coal  in  factories,  which  are  operated  according  to  dia- 
grams 2  to  5,  should  not  surpass  8  to  9%;  it  can,  how- 
ever, drop  to  7  and  8%.  With  a  high  grade  coal  and 
favorable  working  conditions,  it  can  drop  to  6  and  7%, 
and  with  raw  sugar  production  even  lower. 

It  is  unnecessary  to  mention  that  a  well-calculated 
steam  economy  is  of  prime  consideration  for  a  sugar 
factory  which  is  to  be  constructed,  because  the  cost 
of  manufacture  from  the  beets  will  diminish,  due  to 
reducing  the  steam  consumption,  and  the  building  costs 
will  be  lower  since  the  size  and  capacity  of  the  boilers, 
of  the  condensers,  of  the  air,  water  and  ammonia  pumps, 
and  of  the  pipe  connections  will  be  reduced. 

Matters  are,  of  course,  different  if  the  utilization  of 
steam  is  to  be  arranged  in  a  factory  already  in  existence, 
because  then  the  expected  savings  must  be  compared 
with  the  costs  entailed,  whereby  it  will  often  figure  out 
that  it  is  better  to  use  here  a  rather  larger  quantity  of 


96  STEAM  ECONOMY 

fuel,  since  the  best  apparatus  may  prove  too  expensive. 
There  is  still  in  this  line  of  work  in  the  existing  facto- 
ries a  very  profitable  field  for  the  investment  of  capital 
with  good  prospects  for  excellent  returns.  But  very 
often  unforeseen  conditions  will  occur  which  will  annihi- 
late the  savings  through  an  increased  loss  of  sugar  (bac- 
teria with  too  large  a  diffusion,  etc.).  In  a  few  cases 
it  becomes  apparent  that  the  control  of  the  sugar  loss 
is  for  the  most  part  still  very  unsatisfactory. 


INDEX. 


>  PAGE 

Addition  of  lime,  influence  of,  on  steam  consumption  ............  82 

B. 

Boilers,  feed  water  for  .......................................  95 

Boilers,  high  and  low  pressure  .......  ..........................  48 

Boiling,  limits  of  temperature  in  ...............................  68 

Boiling  of  second  product  ...................................  .  .  2 

Boiling  of  sugars,  quantity  of  water  evaporated  in  ...............  36 

C. 

Calculation  of  the  heating  surfaces  ............................  86 

Carbonic  acid  gas,  amount  absorbed  by  saturation  ...............  14 

Carbonic  acid  gas,  expansion  of,  equation  for  volume  of  ..........  16 

Carbonic  acid  gas,  weight  and  volume  of  escaping  ...............  16 

Closing  remarks  .............................................  94 

Coils,  open  steam,  for  heating  thick  juice  and  syrup,  steam  con- 

sumption of  .........................................  84. 

Coils,  perforated,  in  saturation,  expenditure  of  steam  due  to  .......  84 

Condensation  of  steam  occurring  in  centrifugal  basket  ............  41 

Conditions  affecting  steam  consumption  in  evaporation  ...........  33: 

Cost  of  manufacture  and  of  building  affected  by  steam  economy.  .  .  95 

D. 

Defecation,  with  dry  lime,  savings  of  ...........................  21 

Diffusion,  influence  of,  on  steam  consumption  ...................  80 

Diffusion,  limits  of  temperature  ...............................  65: 

Diffusion,  loss  occasioned  by  small  .............................  80 

Diffusion,  losses  in  radiation,  incidental  to  ......................  41 

Diffusion,  steam  consumption  for  ..............................  41 

Distribution  of  steam,  diagrams  for  ............................  70- 

97 


98  INDEX 

PAGE 

Distribution  of  steam  in  the  factory 50 

Distribution  of  temperature  in  evaporating  system 59 

Division,  automatic,  of  centrifugal  discharges 2 

Draw  of  juice,  loss  of  steam  occasioned  by  excessive 80 

E. 

Economy  in  lime  consumption 26 

Economy  of  steam  through  utilization  of  vapors.     Example  15.  ...  52 

Elaboration  (selected  for  book) i 

Evaporating    system,    distribution    of    temperatures    in    several 

bodies 59~63 

Evaporation 29 

Evaporation,   eightfold  may  be  expected,   even  ninefold  under 

favorable  conditions 95 

Evaporation,  influence  of,  on  steam  consumption 81 

F. 

Filter  presses,  steam  consumption  due  to  steaming  off  of ,  28 

Foam  in  saturation,  steam  consumption  for  settling 23 

Formula  for  steam  consumption  for  heating  of  juice  in  evaporation  29 

G. 

Green  syrups,  treatment  of 38 

H. 

Hausbrand's  Table  (No.  32)  for  weight  of  steam  passing  through 

Pipes 90 

Heat  and  steam  consumption  for  diffusion 10 

Heat  consumption  and  heating  surfaces  for  saturations 22 

Heat  consumption  in  saturations,  increase  of 26 

Heat  consumption  per  H.-P.  hour 45 

Heat  consumption  per  pound  of  ice  (with  frozen  beets)  in  diffusion 

station 1 1 

Heat  in  mole-pound  of  CaCO3 21 

Heat  loss  by  radiation  in  saturation  station 17 

Heat  loss  in  diffusion  by  radiation 8 

Heat,  production  of,  in  saturations 20 


INDEX  99 


Heater,  raw  juice,  heating  surface  of.  Example  20 93 

Heater,  raw  juice,  influence  of,  on  steam  consumption 81 

Heaters,  limits  of  temperature  for 65 

Heaters,  s;team  and  heat  consumption  of 12 

Heating  of  juice  in  saturation  station 17 

Heating  of  milk  of  lime  in  saturation  station 17 

Heating  of  saturation  gas 18 

Heating  of  the  thick  juice  and  syrups 37 

Heating  of  thick  juice  and  syrup  with  open  coils,  steam  consumption 

for 84 

Heating  of  wash  and  green  syrups  with  open  coils,  steam  consumption 

for 85 

Heating  surfaces,  calculations  of  the 86 

Heating  surfaces  of  bodies  of  quadruple  evaporator  for  daily  slicing 

of  660  tons  of  beets.  Example  19 89 

Heating  the  juice  in  evaporation,  steam  consumption  due  to 29 

I. 

Increase  of  heat  consumption  in  the  saturations. 26 

Increase  of  steam  consumption  during  saturation 26 

Increase  of  temperature  in  saturation,  due  to  introduction  of  green 

and  wash  syrups 27 

Influence  of  methods  of  operation  on  total  steam  consumption  ....  80 

Information  in  literature,  catalogues,  etc 5 

Insulation,  application  of,  affects  efficiency 44 

Insulation,  relative  value  of  materials  for 42 

Introduction i 

J. 

Juice  boiler  or  Pauly  body 53 

Juice  boiler,  temperature  in 61 

Juice,  thin,  saturation  of 14 

L. 

Lime,  addition  of,  influence  of,  in  saturation  in  evaporation 83 

Lime,  addition  of,  influence  of,  in  saturation  on  steam  consumption.  82 

Lime  kiln,  gas  taken  from,  influence  on  steam  consumption 82 


100  INDEX 

PAGE 

Loss  in  heat  by  radiation 8 

Loss  in  heat  by  radiation,  equation  for 9 

Loss  occasioned  by  small  diffusion 80 

Loss,  radiation,  in  saturation  station 17 

Losses  in  evaporation  station 32 

Losses  in  temperature  in  several  bodies  of  evaporating  system 61 

Losses,  steam,  due  to  radiation 41 

Losses,  unprofitable,  in  evaporating  systems 64 

M. 

Means  to  reduce  lime  consumption 26 

Mechanical  work 45 

Method  for  the  reduction  of  the  total  steam  consumption 50 

Method  of  operation,  influence  of,  on  total  steam  consumption 80 

Milk  of  lime,  heating  of,  in  saturation  station 17 

P. 

Pauly  body  or  juice  boiler 53, 

Pipes,  velocity  and  weight  of  steam  passing  through 90-92 

Preface,  translator's iii 

Profitable  arrangement  of  heating  surfaces 58 

Proportioning  of  stations 87 

Q- 
Quantity  of  water  evaporated  per  pound  of  steam  in  evaporation  .32-33 

R. 

Radiation  loss  in  saturation  station 17 

Radiation  losses  for  wrought-  and  cast-iron  surfaces 44 

Radiation  losses  incidental  to  diffusion 41 

Radiation  losses  in  evaporation  and  vacuum  pans 41 

Radiation,  total  loss  through,  on  weight  of  beets 42 

Raw  juice  heater,  heating  surface  of.     Example  20 93 

Raw  juice  heater,  influence  of,  on  steam  consumption 81 


INDEX  101 

PAGE 

Raw  sugar  from  second  product,  reintroduced 2 

Reduction  of  steam  consumption  in  saturations 25 

Remarks,  closing 94 

Remelted  products,  treatment  of 38 

Rillieux  principles 50 

Rillieux  principles,  advantage  of 51 

Rillieux  principles,  modification  of,  by  Pauly 53 


S. 

Saturation,  addition  of  lime  in,  influence  of,  on  steam  consumption. .  82 

Saturation  gas,  heating  of 18 

Saturation  gas,  influence  of,  on  steam  consumption 82 

Saturation,  influence  of,  on  steam  consumption 81 

Saturation,  limits  of  temperature  in 67 

Saturation  of  thin  juice 14 

Saturation  of  thin  juice,  conditions  concerning 15 

Savings,  how  to  be  considered  in  existing  factory 95 

Second  product,  boiling  of 2 

Slicings,  table  of,  for  daily  capacities  from  300  to  3000  tons 88 

Stations  consuming  steam,  other 49 

Stations,  proportioning  of 87 

Steam  consumed  for  steaming  off  the  vacuum  pans 37 

Steam  consumed  in  saturation.    Example  2 24 

Steam  consumed  in  saturation,  reduction  of 25 

Steam  consumption  due  to  evaporation  in  saturation 20 

Steam  consumption  due  to  heating  of  saturation  gas 19 

Steam  consumption  due  to  introduction  of  green  and  wash  syrups  in 

saturation.     Example  3 28 

Steam  consumption  during  saturation,  increase  of 26 

Steam  consumption  for  boiling.     Example  10 36 

Steam  consumption  for  boiling.     Example  n 37 

Steam  consumption  for  effective  H.P 45 

Steam  consumption  for  evaporation  depends  on 31,  33 

Steam  consumption  for  evaporation,  formula  for 34 

Steam    consumption   for  evaporation   in   quintuple   effect.       Ex- 
ample 7 34 


102  INDEX 

PAGE 

Steam  consumption   for  evaporation   in  quadruple   effect.       Ex- 
ample 8 34 

Steam  consumption  for  evaporation  proper.     Example  6 31 

Steam  consumption  for  evaporation  with  Pauly  body,  formula  for  35 

Steam  consumption  for  evaporation  with  Pauly  body.     Example  9  35 
Steam  consumption  for  heating  wash  and  green  syrups  with  open 

coils 85 

Steam  consumption  for  saturation 17 

Steam  consumption  for  settling  foam  in  saturations 23 

Steam  consumption  for  treatment  of  green  syrups  and  remelted 

products.     Examples  13  and  14 38-39 

Steam  consumption,  influence  of  methods  of  operations  on  total ....  80 
Steam  consumption  in  evaporation  due  to  heating  of  juice  to  tem- 
perature in  first  body.     Example  4 30 

Steam  consumption  in  vacuum  pans  due  to  variations  in  density  of 

thick  juice  introduced 85 

Steam  consumption,  methods  for  reduction  of  total 50 

Steam  consumption  of  individual  stations 6 

for  diffusion 6-10 

for  diffusion,  equation  for 8 

Steam  consumption  of  saturation  for  every  condition 21 

Steam  consumption  of  separate  stations  under  average  operating 

conditions 56 

Steam  consumption  per  I.H.P 46 

Steam  consumption  per  pound  of  ice  (with  frozen  beets)  in  diffusion 

•     station n 

Steam  consumption  profitable  to  stations  other  than  diffusion 9 

Steam,  distribution  of,  diagrams  for 7°~79 

Steam,  economy  of,  through  utilization  of  vapors 52 

Steam  losses  due  to  radiation 41 

Steam,  reduction  of,  used  for  turbinating 40 

Steam,  saving  of,  by  installation  of  juice  boiler 53 

Steam,  saving  of,  by  installation  of  juice  boiler.     Example  16 54 

Steam,  velocity  and  weight  of,  passing  through  pipes,  Hausbrand's 

Table  (No.  32) 90-91 

Steaming  off  of  filter  presses,  steam  consumption  due  to 28 

Steffens'  process,  steam  consumption  of 49 

Sulphuration 28 


INDEX  103 


Superheating  of  steam  of  restricted  value 48-49 

Syrup,  green,  filtration  and  treatment 3 

Syrup,  green,  reintroduction  of 3 

Syrups,  heating  of,  steam  consumption  for.     Example  12 37~38 

Systems,  different,  for  utilizing  juice  vapors 55 


T. 

Table  for  heat  losses  with  various  types  of  insulations 43 

Table  for  steam  and  heat  consumption  for  diffusion 10 

Table  for  steam  and  heat  consumption  for  heaters 13 

Table  of  steam  consumption  due  to  evaporation  in  saturation 20 

Table  of  steam  consumption  due  to  heating  of  saturation  gas 19 

Table  of  steam  consumption  for  saturations  in  per  cent  lime  con- 
sumption and  volumetric  contents  of  COz 25 

Table  showing  conditions  concerning  saturation 15 

Temperature,  limits  of,  for  the  heating  stations 65 

Temperature  of  saturation 27 

Temperature  of  saturation,  influence  of,  on  steam  consumption  in 

evaporation 83 

Thick  juice,  heating  of 37 

Thin  juice,  saturation  of 14 

Third  product,  addition  of,  in  mixer 3 

Third  product,  quantity  in  pan  and  mixer 3 

Treatment  of  green  syrups  and  remelted  products 38 

Turbinating  and  washing 39 


V. 

Vacuum  pan,  water  evaporated  in,  for  daily  slicing  of  440  tons 

of  beets.     Example  18 89 

Vacuum  pans,  steam  consumed  for  steaming  off 37 

Vacuum  pans,  variations  in  steam  consumption,  according  to  density 

of  thick  juice  introduced 85 

Vapors,  compressing  of,  for  evaporation 54 

Velocity  of  steam    passing    through    pipes,    Hausbrand's    Table 

(No.  32) 90-91 


104  INDEX 

W- 

Washing,  turbinating  and. 39 

Water  evaporated  in  vacuum  pan  for  a  daily  slicing  of  440  tons  of 

beets.     Example  18 89 

Water,  evaporation  of,  in  saturations 19 

Water,  kinds  of,  used  at  diffusion  station n 

Water,  quantity  of,  evaporated  in  boiling 36 

Water,  quantity  of ,  evaporated  in  boiling.    Example  10 36 

Water,  quantity  of,  evaporated  in  boiling.     Example  n 37 

Water,  quantity  of,  evaporated  per  pound  of  steam  in  evaporation.  32 

Weight  of  steam  passing  through  pipes,  Hausbrand's  Table  (No.  32)  91 


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